Alright guys i have a 91 rs, 305 tbi, 5 speed. it surges at idel. and when i get going, if i hit the clutch it will rev anywhere from 2500-2800 (my tachs off alittle of course but its somewhere in there) and will come back down to normal idle once i stop, could this be my IAC, or TPS sensor?

 

I would think you have an error code or CE light lit. Only way engine can speed up like that with no throttle movement is intermittant vac leak or IAC opening.

 

its throwing no codes. im gonna check tomorrow for a vac leak. thanks for the input!

 

Mine was doing a similar thing.I would suggest checking the egr valve.That could cause a vacuum leak and is an easy fix.You can check it by simply removing the vacuum line and plug it off(this will make the egr stay closed) then drive the car to see if it still does it.You can also put your finger underneath the egr valve and rev the engine to see if the diaphragm is moving properly.I ended up just putting a egr block off plate on mine and plugging the port where the vacuum line come from for the egr.Hope this helps,if not I have other ideas for ya

could just be carbon buildup on the IAC or the EGR too btw.

 

My car had a really bad surging idle...replaced the ICM and it runs much better now. My car was throwing code 42 though

 

Looks like everyone has u covered ... IAC, tps, egr, vacuum leak ... unplug IAC and just cruise around the block (no spirited driving here) c if it stops , then do the same with tps ... note this WILL set off codes so u will have to clear them by removing the negative battery cable snd turn headlights on for about 10-15 min

 

thanks guys, gonna tinker with it today and see what i can find.the car does have 188k on it. i think its time to start replacing some things anyways.. lol.

 

Im a big supporter of starting by checking the Fuel pressure. Had this happen to me twice. Both times it was a lack of fuel pressure caused by the rotting of the rubber hose connecting the metal fuel lines to the pump.