My idle is a little rough. Sometimes it will smooth out for a couple seconds. I can only get my idle tuned down to ~1100. After that the motor will just die in seconds. I know it is not a vaccum problem. I have replaced any broken lines and gaskets (intake, EGR) that could cause this problem. My IAC and TPS are good. They are on a few months old and tuned right.

Also something that is happening is that my exhaust smells rich after I gun on the throttle and let off quickly, like passing someone. I figure that is a lack of spark, Or it could be the FPR right? Otherwise no rich aftersmell. When it does smell rich it is just for a few moments. I know I need to check my fuel pressure sometime.

Another question is that could a lack of backpressure cause the idle problem. I got headers with 1 broken bolt a leak, !cat, Dynomax catback. My exhaust is headers to 2.5" exhaust pipe (!cat) to the duel oulet muffler.

This idle problem has been baffling me for the past few months and I am clueless now. Anyone have any ideas. Thanks.

 

i have the same exact problem only 1200 rpm i changed all my vacuum lines all i can think of now is that my booster might be shot like these things go every once in awhile and this one never has been changed try plugging the line that goes into ur brake booster then start it and see if there's a difference cause it deffinatly sounds like a vacuum problem. If u find out what it is let me know i can't always get out to my brothers so i just think of a game plan b4 i get cracking on it.

 

Already checked the Brake Booster. Plugged the line and no difference in the idle.

 

check the old fashioned way; put your hand over the air intake hose where it plugs into the air filter. See if you can make the idle go back to where it should be. If it idles down to where it should be then you DO have a vacuum leak. This only works if you HAVEN'T messed with the idle adjust.

The reason I am going through this explanation is that I have been through it already twice. One Firebird, one Fiero. It was a vacuum line both times. I tried adjusting the idle down and it wouldn't go down below 1000 and ran rich. I ended up dealing with a really large rubber vacuum line that plugs into the bottom of the underneath side of the upper plenum.

Hope this helps!

 

I have messed with the idle control. When you say plug the intake hose, you mean like the MAF tube? I am going to block off the EGR tube where it connects with the intake manifold. Last week I put silicone on all of the joints around it and the idle smoothed out alot and went down some.

 

i had to replace my egr and tube , also had a bad fuel pump at idle it would skip just alittle and pop back through the intake on accerlation . hooked fuel gauge up and taped to windshield and drove car it droped below the standard psi so i replaced fuel pump and have had no more problems with it .

 

That is what I am leaning towards. I think that it is something in the fuel system. I have been worried about my pump. I am going to at least replace my fuel pressure regulator. THe only vaccem lines that I have not been able to check are two that go into the wiring harness on the passenger side and dissapear under the motor.