So i recently bought 97 GST it wasnt running i got it running, but it is idling bad and i can't figure out why. ive changed plugs, plug wires, coil is good, and messed with TPS alot. im am goin to replace the IACV soon and hope it does the trick. other than that any other ideas??

 

Are you recirculating the blow off valve?

Make sure you've got NO vacuum leaks, and NO boost leaks. If you have to, google boost leak tester and go from there. With these cars, crappy idle is mostly due to those few things.

 

yes. my engine it is stock.

i have no vacuum leaks. but how exactly do i test boost leak? i will google it, but any other ideas? thanks

 

That's all I have for now. You've got to look at one thing at a time.

Do some research on it, and everything will make sense.

 

so i cleaned throttle body and iacv. check engine went off and car was running fine. as soon as i drive car for a little and it warms up the idle picks up on its own and idles very high. when i give it gas then left off really fast it almost wants to die and drops to about 300 before catchin up and returning to a high idle. also the check engine light came back on while sitting at a stop light idling high. i will check code soon and post. any ideas great needed. thanks

 

I had a very similar issue just 2 weeks ago in my Spyder GS-T. Turns out the positive cable on the battery was just a tiny bit loose....tightened it up as tight as I could and no problems since. Sometimes its the simple things that make us feel stupid, but they fix some seemingly major problems.

 

i checked all battery connections and battery. it is all good thanks for trying though.

i ordered iacv and am waiting on part to get here. i have another question. How can i make my stock turbo spool later. do i need to buy a turbo control? it spools as soon as i touch gas. and also whenever i punch it and slow down fast the car drops idles really low and wants to stall and it sometimes does. what could cause this? bad blow off or bad wastegate?? help please. thanks

 

That is word for word how mine was acting....I'm still contending there issomething not tight or not clean on your battery connections. If it was a bov or wastegate problem it wouldn't only doing it at idle....I would at very least check your wires for corrosion. Mine were really corroded up inside when I pulled the old terminals off. I cleaned them for now but plan to replace the wires soon cause of how bad they were....but since I messed with the connections I have had no problems. I also have a volt gauge on my car and it was reading normal power levels the whole time it was acting up.

 

like i said i took the battery in to be tested and it was good. i bought new clamps for battery i cleaned terminals. ground is good check with dmm. i got the new iacv and installed it today. the car is idling better now. but somethin is still not right. it will idle perfect then every now and then it wil just idle up on its own then slowly drop back down. and always revs high on start up.

 

UPDATE:
so the car runs perfectly when cold. once it is to operating temp it revs around 2k. i turn the idle screw all the way down while the car was warm and running and it still idles high at about 1300. im thinking of cleaning egr valve. i seem to be running out of options. any ideas? runs good until operating temp then it revs high and fluctuates..

no vacuum leaks.
no turbo leaks.
new iacv.
checked tps.
new plugs and plug wires.
cleaned throttle body.