my car usually idles fine for about 2 minutes, then goes into a miss, the tach will bounce for 1000 to 800 rpms and back and forth. You can also hear the miss in the exhaust. Today i had it on the downcline of my driveway and the SES light came on. Turned the car off and back on and it cranked almost started, but died, then cranked it again and it started. What could be wrong? its a 91 camaro with a 3.1

 

Number of things, first things first, check the timing on your distributor, next check your TPS, that can cause the vehicle not to start. Next, check your IAC, pull it off the TB, clean it up a bit and try that, but the first thing you want to do is check why your SES light came on, might wanna pull some codes, im geuss your TPS.

 

I say sticky EGR
remove and clean.
If this "just started happening" it's the most likely canidate.

while what pasky said could be culprits, a TPS will cause ungoddly high idle, I know from experiance.

the IAC could also be a culprit, but the "jumpiness" would be higher and more pronounced, like 500-2500 as the valve over compensates for itself. again, know from experiance and finding the correct IAC is a serious pain.

Timing, would effect the entire band, until the rev's could overcome the hesitation.

If you leave the car off for a few minutes does it start right up and run "ok"?

While driving a long drive, does the car suddenly loose power and run rough?

does your FAR(Fuel Air Ratio) sudddenly shift at the same RPM and load?

if it does, check and clean the EGR.

 

v6sucker, u perfectly dignosed it. it starts up and runs perfect, then after drive some time it starts to bog and run real rough, not wanna go, then jump real quick. How do i clean the egr?

 

well,
1st remove the EGR tube from the intake and the EGR valve.
Clean the intake inlet side with a gun barrel cleaning kit (easiest)
the remove the EGR and hose it down with solvents. I would use easy bake over cleaner first, then degreaser, then brake fluid for the final rinse.
I would also flush the tube a little.

 

i mean inside the part with all the wires? i cleaned down the tube and inside the top part today with carb cleaner, no differance, i replaced the IAC and that made the idle smooth. But its still having the hesitation problem. Could it be a TV cable? If i manually shift front D to 2 then to 1 then take off in 1 shift to 2 then to D it works fine. And i replaced plugs and wires

 

I mean remove the triangle shaped plug, and remove the 2 bolts holding the unit to the manifold extension tube. And then clean the surface, and use the cleaners I decribed, and as a final "break up of lodged dirt" manually press the center hole bottom plate up. It should have resistance, but if it refuses to move, your motor(EGR) gear guide could be locked/frozen.

the TV cable would effect shifting and engine load. Mainly shift points and OD operation. Meaning you would either shiuft incredibly early, or incredibaly late. And you would virutally never reach, or always be in OD. I saw both extremes cause it ddepends on which way the cable is misaligned.

do I need specify to wait till the engine/manifolds are cold before doing this?

 

found out the manifolds cold today doing plugs, and i told myself to wait till they cooled off. Ok ill try cleaning the egr again tomorrow. But i really think its the TV cable. its like it trys to start out in OD then downshifts to 3rd then 2nd then 1st and jumps up to 4K+ rpms. How do i adjust that? or check to see if its right?

 

and also im not sure if i said already or not. But it only does this sometimes.

 

if it only happens sometimes, it may not be the TV cable.

As far as adjusting it, look in the tech articles off the main page. I refuse to drive/own auto's for their failure rate and problems like this.

 

once i do the TV cable im gonna clean the EGR again, i dont have a gun barrel cleaning kit, or oven cleaner. What can i use inplace of that stuff. I do have brake fluid though. How do i clean inside the EGR? It has the plate on it closed. What will happen if i put a plate over the EGR hole and do away with it?

 

got a code, 45, running rich. I adjusted the TV cable, and cleaned the EGR again, nothing.

 

well i took it out for a drive and the idle is still jumping but the hesitation has stopped. But the car has started shifting out of 1st at 4K rpms, out of 2nd at 3500, and 3rd at 4000.

 

that shifting prob, is the TV cable.

Did you look through the tech articles yet?
(ok here is the article---

https://www.thirdgen.org/newdesign/tech/detent.shtml
----)
and brake cleaner, not fluid.
Any good hard cleaner will do, I just listed the best to use.

The running rich, can be a subseqent prob of a long EGR prob. It heavily coats the O2 sensor and it may need to be replaced now.

 

well i drove it late last night to get gas and it did it within the first 2 minutes of driving but no again after that, and no idle problem after that. I did adjust the TV cable. Someone on the transmission board said i probably have a vacuum leak and the torque converter might not be unlocking. Where should i look for a vacuum leak? I dont hear a hissing or anything.

 

behind the middle/lower intake. Lots of small plastic hoses that break.