93 cutlass supreme idle problems

[XGamesJ6]

ive got a 1993 olds cutlass supreme sl with the 3.1L V6....and lately its been having some problems, when you start it up cold it'll idle fine, just like it should, but when you tap the gas it'll hesitate before revving up, if im driving, it'll do the same, you give it gas like your going and the RPMs drop and then go back up. and then after a long driver, if i turn off the car, let it sit for a little bit, then start it maybe an hour later it'll idle really weird, it'll start up, rev up, then go down and almost die, then pick up again, and it'll do this for a little bit then finally even out...any ideas??

Ive replaced the TPS, IAC, and TBI Base Gasket. not sure where else to go

[xeroinfinity]

When you replaced the IAC did you clean out the passages into the intake?

This is part of the IAC system and needs to be clear to work properly.

Though a TB loose or with a bad gasket
would do the same as a vacum leak which
is what it sounds like you are experiancing.

[XGamesJ6]

i did a compelete TBI cleaning, even took off that top cover thing and cleaned all those passages up nice and clean, all is clear

[xeroinfinity]

Check all your vacum lines and your PCV.

Sounds like you have a vacum leak,
and when it warms up the leak gets worse.
When its cold the leak gets smaller.

Let me know what you find.

[XGamesJ6]

checked all lines, and pvc, everything looks secure and no leaks i can see. the problem is worse when its cold, once the engine is at its normal operating temp it doesnt realy do anything, no hesitations or anything, but sometimes it will...and after a long trip, like at a steady 55 or something like that, if i stop, then go again at a light for instance, it'll seem to bog down, and i have to punch it to force it to go..

[richtazz]

You may have an EGR issue. It may be stuck partially open, and is messing with the air-fuel ratio when the engine is cold. Once the car warms up, and the EGR is supposed to be open, it acts normal.

[XGamesJ6]

im thinking about taking it off and giving it a good cleaning. now ive got an update, this morning i started it up, started fine, tapped the gas and the RPMs dropped the quickly came back, well i decided to try something, so i kept tapping it, until finally the RPMs dropped so low it finally died, then when i tried to start it again, it was hard to start, i had to hold the starter for longer, and it started up roughly, and kind of climbed then finally it just evened out and acted normal

[xeroinfinity]

That EGR was my next suggestion.

Also make sure all the intake manifold bolts are tight.

[XGamesJ6]

all the bolts are good and tight, as for the EGR, i cant take it off and clean it, its a digital EGR valve, and i could damage it, also i would need a new gasket if i remove it. maybe i'll take the risk and try to clean it

[xeroinfinity]

You wont clean the EGR much anyway, clean the opening/port below it.

[XGamesJ6]

i'll give it a shot, what kind of cleaner should i use, just some throttle body cleaner or some specialized stuff?

[xeroinfinity]

Yes any TB cleaner should work fine for cleaning the port.

Just try not to get the EGR wet, as if the powers on it could damage it

[Tonglebeak]

This sounds EXACTLY like the issue I'm having with my 88 ciera...keep us updated so I know what to do

[xeroinfinity]

If you ignition system, plug & wires, coils etc, are in great shape then Idle issues are generaly caused by the IAC in the TB.
If that doesnt clear it up then I'd look at getting your injection/fuel system profesionaly cleaned.
You can buy an injection clear kit from NAPA for around $300. Mine paid for its self in a week!

[XGamesJ6]

i cant be 100% sure the ignition system is good, wires and plugs are somewhat new, coils and module arent, but im assuming they are fine. my guess is an airflow/PCM problem, i replaced IAC, TPS. and did a lot of TB cleaning, im going to try and clean up the EGR next and maybe a little on the manifold, see what i can do