now, at idle my engine will rev about 400 rpm above idle and drop back down, and repeat rev, bwum, rev, bwum

its really weird and i have no idea what's causing it

 

tps or vacuum problem?

 

Sounds like the TPS. Probably just needs to be re-aligned or whatever.

 

do you know of a good walk through for this?\

 

http://www.fc3spro.com/TECH/HOWTO/TPS/tps.html

 

My car does this but it's VERY picky on when it does it. The ONLY time it revs to 1500RMP then back down to idle over and over is when 1. My headlights are on and 2. when it is cold outside. So the only time my idle will rev and drop is when it's cold and nightime. If I turn my headlights off the idle will drop down to normal and not give me the problem, but once I turn them on it will rev to 1500 and drop. It's really wierd, and I even checked my TPS with a voltmeter and it's fine.

 

does it smooth out if you turn on the a/c? i'd check for leaks somewhere.

 

Actually it does. So that would mean a vacuum leak?
But also when it's not revving to 1500 and dropping down and is steady at 650, if I step on the brakes *activate brake booster*, roll the auto windows up or down, turn on the AC, turn my steering wheel at a stop *activates power steering* those will all cause my idle to drop to 500 and feel like it may die but never does. Would that also be a sign of a vacuum leak?

I just noticed i'm thread jacking Secondmessiah's thread. Sorry man, hopefully my questions can help you find a problem to your idle also.

 

maybe or your BAC or ACV need ajusting

 

I had the same problem, after adjusted the BAC it doesn't happen anymore.