I see there is some TSB's for low fuel pressure causing a #2 misfire and some issues with G103 and wet 02 connectors dropping out banks but I guess until you get a bit more info it is hard to manufacture a hypothesis at this point. Look forward to some more data!

@haywardsautomotive6156

6 жыл бұрын

Seen the same TSB and definitely need more data like spark plug reading with intermittently long spark line @3 ms, no termination oscillations but that may be the inductive pickup & low kV at start of burn line...like the Pico better. I'm old school plug reader plus sounds like people already had their hands all over this one so who knows what he'll find...it's just starting to get good!

@PineHollowAutoDiagnostics

6 жыл бұрын

Thanks for the input, Eric! Have not seen that TSB....I should look at more TSBs haha! We will get some more data in Part 2 ;) Now tell Keith to get over here and share his thoughts! I wonder if he has seen this problem before on the Island? He did mention something about turning on the headlights and causing more misfires...crazy stuff lol

@PineHollowAutoDiagnostics

6 жыл бұрын

Eric, I am curious, what would be your next step in this diag? What other data would you collect?

@haywardsautomotive6156

6 жыл бұрын

Keith is a smart cookie b/c the same ground (G104) for the 2,4,6,8 coils is also for the headlights by Mitchell for 5.3 but then their ground distribution shows G102 for all the coils & BBB shows G102 for grd distro & engine diagrams so I know it is in capable hands to figure it out if needed. It only takes a second to test...looking forward to the outcome. I'd also test the secondary of the good coils and see what you get for a waveform plus it only takes a second to pull a plug on a 5.3 I know it'll be good and there is always an important nugget your holding :D This as a low mileage Avalanche so did it just come out of storage or just driven low miles. Part II should be good. Of course these are all inconclusive conclusions from insufficient data b/c I can still list a lot more possibilities. Good suspense Ivan :D

@SouthMainAuto

6 жыл бұрын

My next step? I would assume it would be the same as anyone's... find out why it is misfiring haha. What's missing, fuel, spark, compression, timing, ability to breath? I would monitor as much as I could at the same time on the cylinder that was acting up the most. I guess at this point in the video not enough data is gathered to make an assumption. What data would I collect... hmmm If I knew 100% for sure spark was good, power, grounds good at coils I would gather injector drop and injector current along with fuel pressure just because that can be done easy enough, if fuel and spark were perfect and being delivered at the correct time and all I would go in cylinder and see if there is a valve spring or valve issue in general, like I say at this point I could make a big old list hah. WE NEED MORE DATA IVAN!!

interesting case study as usual,waiting for part 2 great job ivan, cheers.....

This is super interesting. Can't wait for next part.

I know this is an old video but it really helped me narrow down my issue. I have a misfire in the #2 cylinder in a 03 suburban 340k miles on it. I changed coils wires and plugs since I know these needed to be changed. Still a slight misfire but it runs much better. I unplugged bank 2 upstream and downstream o2 sensors. It runs a little better. I will just replace all 4 sensors. Thank you for this video. I was ready to junk the Chevy and buy a new one.

Another great video Ivan I won't spoil it for everybody we will wait till Part 2 great video

@PineHollowAutoDiagnostics

6 жыл бұрын

No worries Leon, did "car whisperer" Keith already tell you what's wrong with the truck? xD

@bodgitandleggitgarage

6 жыл бұрын

Pine Hollow Auto Diagnostics hahah no I told him

@YungCaliber15

6 жыл бұрын

I know as well 👀

@joeshearer1247

6 жыл бұрын

bodgit and leggit garage yea right Leon you have these trucks over there?

@bodgitandleggitgarage

6 жыл бұрын

Joe Shearer hahahah no never even heard of it before lol

I'm digging in the couch cushions for change as we speak... In anticipation of part 2! 😎😎😎

@PineHollowAutoDiagnostics

6 жыл бұрын

YES! hahaha

Thanks bro this video helped me a lot and each time I learn more!!!

Good video Ivan going be waiting for number 2

i was going to say hairline crack in coil pack but this runs 8 individual coils so there goes that,maybe do a coil check to see if any sign of cracks..back to basics plugs wire and earth resistance. this DIY can't wait for part 2 now Ivan.

After considering a few options I’d probably still go with “ ignition related “. First clue : severe misfire with flashing check engine light on cold start up after heavy rain,that gets better once warm. The spark line seemed low. Second clue : lean code you haven’t talked about... I would still approach this in layman’s terms and just swap coil/plug with a “ known good “. Seems pretty straight forward... Thanks for the video! 👍

@PineHollowAutoDiagnostics

6 жыл бұрын

Yes! The lean code! Could be due to the misfires...but fuel trims looked perfect so far. Part 2 will get interesting :)

@nicknicu1787

6 жыл бұрын

Pine Hollow Auto Diagnostics Did you look at fuel trims before or after resetting the CEL?

Hey Ivan! Hope your doing well from Pittsburgh. Spring is never coming! Haha. Question.. 04 Liberty 3.7L, got a code while cold idle still open loop for a O2 bank 2/2 low voltage a couple of weeks ago. Cleared and hasn’t come back. I did notice my LTFT is +10 Lean on both banks and fluctuating properly around zero on both STFT. Would you be concerned. How much influence does the downstream O2 sensors have on the LTFT’s? O2 sensor 2/2 does read a lower voltage thank 1/2 once warmed up. Should I throw parts cannon and buy two downstreams? No codes atm. Slightly rough idle at open loop. Can’t locate and vacuum leaks

It's been interesting so far. I'm most familiar with GM than anything else but even that doesn't help much here. However, my 5.7 liter had an intake gasket leak and that allowed water to get into the cylinders which fouled the spark plugs. That's all I got Ivan. Looking forward to the next video.

@PineHollowAutoDiagnostics

6 жыл бұрын

Actually Wyatt, your guess is closer than most in the comments...you will see what I mean in Part 2 :)

I had a chevy express had steady misfires on a few cylinders at 2k rpms, crankshaft relearn took care of it... A few years ago i had a truck that had a few worn camshaft lobes made no noise and cause a steady misfire at idle and went away while driving it... Ive seen broken valve springs but not do what this is doing. and i don't know if it has active fuel management but the cylinders the shut down are 1,4,6,7. I can't wait to see what you end up with. I love seeing different faults it makes it more interesting!

Headed to part 2, no delayed suspense for me :-)

If I had to guess, since I own the same engine & know it's history, I'd say busted valve spring ... but that seems to happen on the '07 and up ones more than these years, in addition to bad camshafts and stuck AFM lifters. GM sure knows how to build engines after 100+ years! It seems they're regressing in that aspect ... Need more data either way - looking forward to Part II ! :)

in cylinder running bank to bank comparison use pico look for pressure rise difference excellet video Ivan thanks

Good video Ivan. I can't wait for Part 2. I hope it won't be a Pay-per-View. lol :-)

@PineHollowAutoDiagnostics

6 жыл бұрын

LOL November is the last moth for paid videos! Thanks for the idea ;)

Exselecte diagnostic amigo nice video

Thanks bro really helpful 👌 👍 💯

The low coolant is my main clue. I would try a liquid co2 tester to check for a head gasket leak. If it shows nothing, I would go with the other viewers comment about a leaking fuel injector on number 4.

Cracked or leaking exhaust manifold before pre cat o2??? Although fuel trims looked ok?... looking forward to next video :)

I was told by a 20+ year GM Master Certified Tech that it's not uncommon for the Misfire counts to sometimes count up on cylinders that are actually working fine in a dead miss situation. Especially on the cylinder that fires just before and just after the dead cylinder. But it can be on any of the other cylinders. So keep in mind the firing order whenever doing a misfire diagnosis. It could be counting up wrong cylinders. He strongly suggested to me that in a misfire diagnosis, fix the dead miss FIRST, THEN go back and watch the misfire counters. Otherwise if you only get your data while the dead miss is still happening, it can really bite you in wasted time

Something in the harness. Wiggle test it. Can the coils be swap around. Bank 1 to bank 2

Ok I finally watch the video burn time looks good but where is the primary switch on can't see ignition coil charge or is it just the way you have the scope setup

@PineHollowAutoDiagnostics

6 жыл бұрын

The waveform looked kinda weird, but the spark was definitely occurring inside cylinder based on the burn line...

@bodgitandleggitgarage

6 жыл бұрын

Pine Hollow Auto Diagnostics yes but what about the switch on ignition coil charge I did not see it in the waveform

@PineHollowAutoDiagnostics

6 жыл бұрын

Not sure...all I know is that coil definitely fired lol

The ignition advance seems all over the place. I wounder if this is a crank sensor problem?

Best guess, someone had some plug wires off and didn’t connect them fully? LS wires can be a pain to connect and have to hear two clicks before they are fully on

O2 sensor bad cause one side no fuel? I have misfires on 2,4,6. I’ve already throw a long list of parts on it. Do I replace the O2 pigtail and sensor? It’s vg30e ‘93 pathfinder.

@PineHollowAutoDiagnostics

3 жыл бұрын

Yup replace the O2 sensor. Denso or NTK only :)

Great vid!! I’m guessing small coolant leak in head gasket between #2 and #6, on a cold start it misses more because it’s trying to burn the coolant that’s been slowly leaking in the cylinders. Sets more misfires at idle because it has less pressure blowing it out the exhaust valve then when reving it, also computer has more time to calculate somethings wrong. Funny smell might be burnt coolant in exhaust stream, flashing engine light maybe because saturated cylinder but could have also been the coil connecter that was unplugged. I also kinda think the wave looks funny, possibly coolant affecting it. That’s my theory?

@PineHollowAutoDiagnostics

6 жыл бұрын

Not bad! I like your thought process! You did explain all the data presented :)

Ivan, i doubt the spark plugs would be excessively worn out at 67k. They are iridium and should be good for 100k and in reality a lot more than that. I have an 03 silverado and changed mine at 127k and they were still working fine. My best guess is intermittent coil drivers in the ecm? Corrosion on the ecm harness?

Have the whole passenger bank not firing with a o2 sensor on same side had a code, could this actually stop the whole bank from firing.

Curious of the history as with so few miles in 13 yrs, does vehicle sit through winters while owner vacations in the south?

There are a number of comments suggesting bad ground connections. This could be eliminated with a few jumper wires to a solid ground on the engine and/or battery. This is a tough problem.

Good proposals. I'll add mine to the collection: Either low coil primary voltage OR low compression in cylinder #2 (based on ignition waveform). Sticking (dirty) hydraulic lifter on #2 intake valve, leading to a tight valve and air-fuex mix leaking back to intake during compression stroke. Misfire indication on #2 due low power / no power. Extra fuel vapor in the intake MF + normal amount of fuel injection cause too rich mix to #6. Poor output -> misfire indication. Overall AFR still right -> fuel trims ok on bank 2. Repair: Oil change, lifter cleaner addtive to oil.

@PineHollowAutoDiagnostics

6 жыл бұрын

Great thought process. I like that you explained how the fuel trims are still OK, even with the misfires :)

A few days ago I looked at A 07 escalade with a 6.2 ..very similar situation. I found a small amount of coolant getting into cylinder #2. Coolant was a bit low. Ran terrible upon cold starts but ran ok when hot but I could see some misfires on the scan tool. So is say you may have a head gasket issue...or broken valve spring. Thanks for The vid.love these cliffhangers

@PineHollowAutoDiagnostics

6 жыл бұрын

GM 6.2 are nighmares lol

@theadventuresofjavier8698

6 жыл бұрын

Pine Hollow Auto Diagnostics amen to that!😭😭😭😭😭

@cojones8518

6 жыл бұрын

3.x L lower intake gaskets

@Micko350

6 жыл бұрын

Pine Hollow Auto Diagnostics Ivan you cannot have a nightmare without any 'T' 😂

@theadventuresofjavier8698

6 жыл бұрын

Michael O LMAO...he said it Mexican style so I could understand...😂😂😂😂😂😂

Odd spark plugs fitted between cylinders, or it needs a new set of plugs in general, Cold start dead miss though not sure if weak plugs would cause that, more like coolant in cylinder in that case.

Just going on the secondary waveform you logged, is it just me or when car starts to shudder, does the voltage after the burn time increase, i.e. indicative of a lean condition causing misfire? If it happening on just that bank, perhaps it's an inlet manifold leak as engine warms up? Would expect to see O2 sensor reporting a lean condition too once warmed up (which I think you had a code for prior to clearing them). Keep up the awesome diagnoses!

@PineHollowAutoDiagnostics

6 жыл бұрын

Great observations! That P0174 Bank 2 Lean turns out to be quite important ;)

A New York State Birdy Tells me that a certain Mr.Ivan might be going to Krown Town Soon ;) EXCELLENT CHOICE!

@PineHollowAutoDiagnostics

6 жыл бұрын

As soon as I get a bit of free time lol

@lightningsmokerXx

6 жыл бұрын

If you do , PLEASE FILM IT. Don't forget to ask about the Salt Eliminator & Silicone the Door Rubbers. Apparently Krown makes their own silicone spray & has more silicone in it than most.

I have a 2007 1500 with Cylinder deactivation 5.3. Kinda does the same thing misses at idle but runs perfect.

@jasonpsapp17

4 жыл бұрын

Same, any luck?

If it was something bank specific ( fuel/vacume leak )you would expect the fuel trims to be countering ,my guess is spark happening outside the cylinder

Throw some plugs and wires fix your ground and call it a fix 😁 let's see what's next Ivan...

There doesn't seem to be any coil oscillations left at the end of the waveform. There should be around 3 or 4 'rings' remaining to show a healthy coil.

Ivan, I'll mail u a dorman hat.....

its the air intake manifold gaskets. i had the same problem with my 5.3l

If it passes the water test I would check for intake gasket leak? Keith

I have a 2002 Chevy avalanche that dies when you drive it why is that I change my spark plugs and the wires and the coils too but it keeps die on me just want to know what I can do

I always check firing order when seeing 2 cylinders misfiring. On these 5.3 2 and 6 fire 1 after the other

I would do a relative compression test, just for the sake of it. And then maybe switching the coils and looking if the problem follows? And your coil waveform looks a little strange, looks much different than what I've seen on Scannerdanner videos. I guess there might be some weirdness going on with the ignition.

Well, secondary ignition waveform shows that the energy isn't dropping down after the burn time. It's slowly trailing off. It isn't being completely dissipated showing an issue with the coil. Since this isn't Staten Island, you could compare waveform to another coil or do the old swap routine to see if it follows.

@PineHollowAutoDiagnostics

6 жыл бұрын

The waveform looked kind of weird. I should have checked a cylinder on the "good" bank!

@baxrok2.

6 жыл бұрын

If it wasn't the coil, then that weird waveform would seem to indicate that it's something internal to the combustion chamber.

@PineHollowAutoDiagnostics

6 жыл бұрын

Indeed...what is weird inside?

@baxrok2.

6 жыл бұрын

Pine Hollow Auto Diagnostics The burn time is all over the place. So, hydrocarbons are not fully being burned. That lean code could point to some unmetered air. Perhaps a ScannerDanner style soda bottle water test for a vacuum leak? But! Fuel trims looked good so, fuel injector issue perhaps.

I would have said head gasket or some sort of air leak but would a HG issue show up on a compression test?

@RicardoPCGamer

6 жыл бұрын

Michael Manley yes

I'd swap the coils and plugs between 1 and 2 & see if the problem moves with it, But my gut says it's ground related.

Really it's acting like a vacuum leak on the right side but fuel trim data doesn't bare that out, sometimes the simple answer fits best, poor atomization of fuel at idle, possible fouled plug. we know the truck has low miles for it's age. A stuck EGR valve would affect both sides same for lack of service; air filter, plugs, this engine is not vvt so can't be a cam phaser, you can't hear a vacuum leak or at least don't suspect one, coil voltage ramp rules out bad ground or coil, so we're left with something on the right side. looking forward to part 2

I would like to know because I have a 5.3 that is doing the same thing except on 3 and 7.

Has it had new plugs installed. If it has my call is not the factory correct plugs. These ls moters don’t like anything but dubble platinum plugs

Could it be the Plugs? Hope your cold leaves soon. Enjoy your video's.

@PineHollowAutoDiagnostics

6 жыл бұрын

It could absolutely be the plugs. By why so consistently only on one bank??

my shout is incorrect timing chain adjustment from factory, so slight, eg one toothe at cam, so that it doesn't effect performance until now in its life a very slight MAF or O2 miss reading causes it to miss fire on that bank.

I know this is an old video but I have a 2003 suburban and it had multiple misfires and flashing engine light. Burned fuel like crazy and I was smelling gas at the tailpipe. It shook so bad that the exhaust pipe was banging and every time I started the engine I would hear popping in the exhaust pipe. Shop told me I needed new fuel injectors. I did not do that because I’m dumping fuel. I watched this video and did some testing. I ended up changing all four O2 sensors and mass air flow. After that I was able to find I had misfires in 1,3 and 4 cylinders. Changed coils and plugs and wires and the engines runs like new. I purchased the suburban used and the engine light was on. Now no lights are on. The power is there and gas mileage is great. The shop was ready to throw parts at it. I don’t know what diagnostic tools they had but they were wrong. I am still using the injectors that came on the vehicle. Thanks for sharing this video.

I would do an in-cylinder compression test using a pressure wave transducer, I want to rule out valve train problems. Misfire on Cylinder 6 maybe due to the firing order, the ecm perceives a misfire on 6 due to a misfire on cylinder 2.

I keep hearing a squeaky/ poppy noise. Is that pesky belt making that? If not possibly a leaking exhaust manifold gasket specially on cold starts would cause similar circumstances.

@PineHollowAutoDiagnostics

6 жыл бұрын

yeah just a squeaky belt haha

My next step would be swap 2 and 4 coils with 1 and 3 to see If misfire travels. If it stays the same check injector balance test for bad injectors of course check for proper fuel pressure key forward engine off then engine on then under load.

Pull de plug! It would reveal oil/carbon shorting. Wiring harness could be shorting the injectors open intermittently. Smell the exhaust for rich mixture.

@PineHollowAutoDiagnostics

6 жыл бұрын

Best guess so far, William. The exhaust did smell a bit funny to me. But why did fuel trims not go negative when this happened?

Need to check fuel pressure regulator diaphragm rupture possible

Those engines are notorious to have problems with the intake gaskets

My thoughts on this were with the majority.....some kind of earth fault...but then again... Could it be...mmm...think i'll await part 2

Good possibly be a bad block ground to the negative side of the coil packs

@PineHollowAutoDiagnostics

6 жыл бұрын

Interesting thought! Is it a different ground for the two banks?

@thedrivewayman3833

6 жыл бұрын

Pine Hollow Auto Diagnostics Yes

@mattway3496

6 жыл бұрын

This was my thought as well

@mattway3496

6 жыл бұрын

Worse in park than under load

@Clete88

6 жыл бұрын

This a good suggestion. It also COULD explain why the misfires improve under load as the engine twists slightly in the mounts.

no guessing, trying to reason it out and up to now there is to less data/evidence to make an educated guess though. Observation is that firing kv seems to be LOW (even on snap) and the firing time in occasions goes up to ~3 ms with the spark line pretty flat. But the spark seems to happens in the combustion chamber....

@PineHollowAutoDiagnostics

6 жыл бұрын

Excellent observations. What other data and evidence would you like to see? What would you do next?

A leaking head gasket that leaks more when cold then seals when it heat expands.

So what’s the problem?

seeing that you have a bi directional scanner id try a crankshaft variation relearn to see if it makes a difference. i seen bank 1 misfiring too. free and easy for you.

@PineHollowAutoDiagnostics

6 жыл бұрын

I also thought of doing this. However, the truck was physcally shaking during the constant misfires, so I believed the counters overall.

@philh9238

6 жыл бұрын

wiring harness being pulled by engine movement. maybe coil current ramp when dead misfire occurs

Hey ivan it will appear to maybe a vacuum leak around the intake or something effecting that bank

@PineHollowAutoDiagnostics

6 жыл бұрын

But then why did the fuel trims not show this? I was very surprised to see the fuel trims being so steady and close to zero...no difference between Bank 1 and 2...

Sounds to me like it needs a new windshield wash pump... ;)~ JK...I'm still stuck on that Eric O evap code which turned out to be faulty p/s sensor...

@PineHollowAutoDiagnostics

6 жыл бұрын

Yeah that was a crazy case study! Wish Eric would have used a PicoScope instead of the Vantage Pro so we would have seen the electrical noise at the fuel tank psi sensor!

I feel like it's the intake manifold gaskets.

Nice one! But we needed to see another cyllinder waveform before the guess game )

@PineHollowAutoDiagnostics

6 жыл бұрын

Yes Vladimir, I should have checked a "good" cylinder on the opposite bank. Dang it haha

@MrBorntoroll

6 жыл бұрын

Guess we just wait and hope part 2 is going to be free ))

Intake manifold leak on passenger side, driver side starting to show same issue.

@PineHollowAutoDiagnostics

6 жыл бұрын

would a vacuum leak show itself in the fuel trims? The long and short terms looked the same for both banks...

@esmith836

6 жыл бұрын

oh yeah it would

@richardcranium5839

6 жыл бұрын

not necessarily in a maf engine (if this is one) it would only adjust to the air moving over the sensor

I'd only be guessing but I'm guessing a vacuum leak. Lean codes and misfires but you haven't given us much else to go on lol

@PineHollowAutoDiagnostics

6 жыл бұрын

Yeah I know haha that was mean of me. However so far I have not seen a theory that would explain ALL of the observations in Part 1 ;) Some very good guesses though! I honestly would never have guessed the actual problem on this truck myself after watching Part 1 lol

Im just guessing and gonna say intake gaskets. But i believe u said it was running fine on cold start up so now im not sure 🤔 😩😳

Oh no no , I need an in cylinder and a injector drop test to be certain sir . Scope pattern to crappy

@PineHollowAutoDiagnostics

6 жыл бұрын

Injector drop test? Fair enough. Part 2 coming right up ;)

@haywardsautomotive6156

6 жыл бұрын

Actually the waveform showed a rich fouled spark plug or carbon tracking just didn't have the detail of a Pico. Definitely needed more info though

I think it has a cracked spark plug that is showing up more when cold

Bet it's clogged or dirty injectors. Dripping at idle but under load fuel pressure overcomes dirty nozzle and added fuel stops miss

@PineHollowAutoDiagnostics

6 жыл бұрын

hmmm I guess it's possible. But with leaky injectors I would also expect Bank 2 fuel trims to go significantly negative, and maybe a Rich code?

I'm sticking to my guns on this one Ivan 🍻 so far lol I will keep zipped for the time being

@PineHollowAutoDiagnostics

6 жыл бұрын

Please share your thoughts with the class, Will! You might even win a free PHAD t-shirt if you are correct ;)

@bodgitandleggitgarage

6 жыл бұрын

I want a free t-shirt but there is one problem that means I have to watch the video😝😝😝😝😝😝

@PineHollowAutoDiagnostics

6 жыл бұрын

There are worse ways to waste your time on the internet hahaah

@robinsonsauto

6 жыл бұрын

Pine Hollow Auto Diagnostics Ok 👍 I will give my best giving the info gathered so far. I may be wrong 😂 first I thought ok let's have a peek at everything in common for the even cylinders 2,4,6,8 a quick glance at a schematic revealed they all 4 share power and ground. However once you started monitoring we found 2&6 were mostly effected and you mentioned it "felt" more as a single cylinder misfire. That put my initial thoughts on the side. then I started thinking what dose 2&6 have in common? Hmm firing order! 18726543 Bam. 2 then 6 at that point my mind is convinced we have a issue with cylinder #2 effects showing on 6 however feel #6 is ok "logical assumptions" my next step would be visually check #2 coil and wire. my feeling is you might see something obvious with the coil or wire. the spark plug is a little less likely but must check as well depending on finding. we just don't know. However we must not forget what's in common. The rest honestly and everything to this point are assumptions on my part. Until I got my eyes on the said. Cylinder 2 final answer 😂😂😂 for now hahaha love your content Ivan

@Micko350

6 жыл бұрын

robinsonsauto that'd be even bank if it's 2, 4, 6 & 8?!

also, if you have one bank with misfires, do a smoke test, check the Integrity of the intake manifold gasket. Because it seems to misfire at idle when manifolf vacuum is the highest

@dylankinch2735

6 жыл бұрын

stanghp1 the fuel trims were fine though. Dont u think a intake leak would show up in the trims

@PineHollowAutoDiagnostics

6 жыл бұрын

Good theory, and follow up question :)

Bad maf?

Diagnosis was?

And probably the primary coil codes were triggered by someone unplugging the connectors

@PineHollowAutoDiagnostics

6 жыл бұрын

That was my first thought. Wanted to start from a clean slate!

Can't tell. It's either missing spark, fuel or compression. Pray it's not the last one, that one's the hardest to figure out.

@PineHollowAutoDiagnostics

6 жыл бұрын

What would you next if you were in the diagnostics hot seat?

@opl500

6 жыл бұрын

Well you said the fuel trims look good. I'd look at ignition first then fuel then compression/exhaust.

Because of the age and low mileage I would think of a corroded ground connection or wire that has a bad connection.

I would spray spark plug wires down with water and have someone power brake it. The rain in the morning is a clue, have seen a lot of GM vehicles with failing wires some times it's the easiest things. Keith

@PineHollowAutoDiagnostics

6 жыл бұрын

Great first step. It would be a big coincidence for all 4 coils/wires to start failing on one bank all at the same time however...

@AutoBikeTruck

6 жыл бұрын

That is a good idea keith frisell !!

Mouses having fun in the engine bay?

possible causes ignition coil,air leak

Bad Spark plug wire, looks like its firing in the cyl. but at times firing outside the cyl. Maybe bad plug, but I say wire! Iv been fouled with gm misfire counter 1 time, butall other times they are spot on.

I hope secondary ignition waveforms on the se ond part 😁😁

@armandonika

6 жыл бұрын

Writing too soon 😂😂

@armandonika

6 жыл бұрын

Low kv probably as a lot of techs said bad ground so the coils can't build enough voltage...

Sounds as though half of the cylinders aren’t firing. I thought gm had vehicles that shut down 4 of 8 cylinders to save on fuel.

@PineHollowAutoDiagnostics

6 жыл бұрын

It read "9.8mpg AVG" on the display hahaha

@InsideOfMyOwnMind

6 жыл бұрын

James Nasto The only way GM ever saved on fuel was with a crank no start.

@RicardoPCGamer

6 жыл бұрын

Gm did not start using that cylinder deactivation system until like 2007 or so. This Truck is a 2004

Need Keiths' mojo right now.

@richardcranium5839

6 жыл бұрын

thats a mental picture we didnt need lol

I'm going to say coil. Didn't see coil oscillations. Maybe the other coils are failing

👍👍

dose it have active fuel management

@PineHollowAutoDiagnostics

6 жыл бұрын

what is active fuel management? No fancy systems on this one...

@johnd8651

6 жыл бұрын

Uses oil pressure to deactivate cylinders via the lifters. AFM lifters are known to stick closed and cause a misfire. Your symptoms could be be related to this. Possible clogged ar sticky lifters?

Look at the plug wires.

@PineHollowAutoDiagnostics

6 жыл бұрын

I did...they looked OK.

My guess would be a bad injector on #4 cylinder, its the only 1 not misfiring on bank 2 which means the O2 sensor making corrections that r good enugh for cylinder #4 hance y u dont see any FT faults

@PineHollowAutoDiagnostics

6 жыл бұрын

Interesting theory. What do you mean by "bad injector" like flowing too much or too little? Would you expect negative fuel trims then?

Seriously though, what about intake manifold issues on that bank 2, maybe smoke test is in order?..Remember this is GM...

If it has low miles then it's probably been sitting forever. I was going to say seriously bad gas had messed up the injectors but weird it would only effect one bank

@PineHollowAutoDiagnostics

6 жыл бұрын

just like that Ford dump truck huh :D

Are you a one person / man shop?

@PineHollowAutoDiagnostics

6 жыл бұрын

yup just me and Diagnostic Dog haha

@QueenCityHistory

6 жыл бұрын

Ivan is a Renaissance man....he doesn't need anyone else. I mean the man fixed an eye glass cutting machine!