I have often taken misc parts off on my 2000 Toyota Celica GT. I was so used to fixing it. This was an old car with many worn out parts. Well, this time I have replaced the intake manifold gasket and when I reassembled, I messed up on reconnecting the vacuum hoses. That was when the nightmare started. My car started to sucked in motor oil into the intake manifold and burning it causing big white cloud of smoke. I have spent a lot of time trying to see what I have done causing the car burn oil. It took me more 6 months to finally fixed it correctly. But in between those time intervals, I have rebuild the whole motor and still didn't fix the issues. The issue was so simple but it was overlooked. I hope you never get into this issue what I have faced. I felt dumb but hey I rebuild the whole motor and it ran great after i solved the oil into the intake manifold issue.