Tech Question

i have a 1989 acura integra 4cyl LS(i think). i have been trying to fix this car and no one seems to know whats wrong with it.
well here goes, when you start the car it will usually run fine for like a minute or two, but then the idle proceeds to race @ about 2500-3000 rpm. then after it does that for a while it will fall down to like 200, and surge up and down trying to stay alive. this is all while in neautral. when in gear the car rev's constantly from 1k to 2500. i would appreciate any help you guys could give me. thank you.

i was told it could be a tps sensor bad, happens my teg to, seems to stop when a new battery is put in.

if you're getting a check engine light which I would imagine you are, pull the codes from the ecm and see what it's telling ya.

I doubt he's getting a check engine light. This thing happens to a lot of cars and could be a few different things, could be a sensor like audiophile said, but I've also had that happen to my accord because I had a hose that had a leak in it, replaced the hose and it was all fixed.

Yes like kicker said it could be a vacum leak. It could also be the IACV if the 89's came with them, not real sure about the pre 90's.

what about the fast idle valve