my cars idle slightly goes up and down somtimes while stopped. it does this somtimes very slightly and i can see my rpms go up & down from 500 to 550 slightly and stop. whats going on with the car? is it a vacum leak some where? does somthing need 2 be ajusted?(new TPS,fuel pump,fuel filter,o2,intake sealed,new vacum lines,presure reg and injectors).

 

Slighty erratic idle can sometimes be caused by a faulty PCV valve...

other than that, im not completely sure. Maybe your timing is a little off?

 

Either it's a missfire or a vac leak. This is how I tell I need to do a tune up.

 

i have this problem too...i was going to post but good thing i read it....mine jumps up to 700 rpm and back down to 500rpms

 

yeah i fogot 2 add that i also changed the PCV last week. this guy told me he did my timing but i think he was a lie. i was also thinking it was the timing. i can see also my battery voltage thing move up and down along with my RPMs. im confussed As 4 red1992v6, u may have a problem with a leaking intake. i just bougt intake mainifold gaskets and resealed them. my car was doing the same thing.