Vacuum Nightmare
I've been meaning to post this for weeks but didn't know exactly how to describe it so here goes :
I'm pretty sure this is vacuum issue, but it happens a LOT more often on colder days (like below 65 degrees or so). First start in the day, motors cold, idles HORRIBLE and bucks (you've probably heard me mention this before). Once it warms up it settles down a little bit, but if I sit at a light for a long period of time, the check engine light will come on, and it'll buck pretty violently again, sometimes so bad the engine stalls. The engine code is for the oxygen sensor, go figure (I replaced this already).
When the light is on, the acceleration is poor. I found that if I goose the throttle a few times in neutral up to about 4k rpm and let it rev down (effectively pulling the vacuum away from the extremeties of the engine) the light will go away until the next time I sit at a light for a long time again. Another tipoff to the vacuum idea is because the air conditioner reciruclator flap will thump into place after taking about 8-10 seconds after pushing the button.
On warmer days its not as prominent (The bucking and CEL) but it still happens after sitting at lights.
Weird huh? More sensitive in colder weather, more violent in colder weather, and vacuum issues. I average 16.2 mpg with this new motor where I got well over 19 with the old one. I also have a line missing off the underside of the intake where about a 3/8" vacuum line goes but I can't find any exposed accessory missing a vacuum line anywhere else. Milkboot's M50 has the same missing line but no issues like I do.
So.... wtf?
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