I have a 91 trans am with a 305 tpi T-5,and when I stop at a stoplight or whatever and I press the clutch in the engine revs up a little and slowly,I mean SLOWLY goes back down to idle..I'm not getting any codes but this drives me crazy...Thanks,Dave

 

its normal, its part of the iac throttle follower function.

 

can i get a second on that?thanks man..

 

ill be second!!!

yes its normal...the 86 mustang gt at the shop does the same thing you explain

 

take your foot off the gas

 

funny

 

Check to ensure your throttle is returning to rest on the idle screw. I had the same problem which was caused by the butterfly valves sticking on the throttle body bores holding the throttle open which cause the throttle position sensor to be open a bit telling the engine to rev up. You may need a stronger throttle return spring. Your throttle position sensor could be slightly out or worn, likewise with the idle air control valve, you could have a vacuum leak you could possibly even need a new ECM but that is unlikely. This was referred to idling up by mechanic and is documented in my recent post.

 

How high does it rev up?
Does it do it when you are stopped and just press on the clutch, or does it do it only when you are moving?
I have a 91 formula TPI 5 speed, very similar to your car, except for a recent engine rebuild and a cam upgrade, and I have not noticed anything abnormal with my engine when I press on the clutch. The car tends to idle a little higher, about 1000 - 1200 rpm when moving and I press the clutch, but not while stopped.

 

Could also be the nut behind the wheel.

 

Are you saying that when you are already stopped sitting at the light and you have the car in neutral, you press in the clutch and the rpms go up?

Mine will rev up a bit when I push in the clutch while I am still rolling and am about to stop, then it slowly drops down.

 

thanks for your really original

 

Nah,Its doing what you described yours does....I've been outta town for work and havent had a chance to look at the thing...Thanks for all the help guys...Dave