I believe thats what the IACV is, a solenoid valve, and the ECU controls the amount of air passing through it by pulsing it open and shut with a variable duration.

 

yah i know... that's what's kinda making me think now it might be more an electrical problem... cause if they replaced the IACV and it was the whole unit... it would fixed it. Maybe it's associated with something else? Is .052-4.58 the correct voltage range for the TPS?

 

bump. i want to know what happened, any updates?

 

nothin new... on my way home i got another CEL... same ol' didn't even bother resetting. I realized though... that when the CEL comes on and the idle jumps to 2000, that if I turn the car off then back on again, it idles normally (normally being still fluctuating for a while then finally settling to normal). oh well I'll leave it on until monday when i take it to the dealership.

 

Ok check this. the car is a 94 integra, ran perfect with no problems. So we did an LS/VTEC setup on it, we just threw a 2000 civic si head on with these parts. B16a2 head, b16a2 intake manifold, Integra LS throttle body, old school95 civic intake temp sensor, b16a2 iac selo. and now we have the same problem as you guys. its totally the same. idles wird, its like at 1500rpm and drops and rises. same simptoms as your, any one have any ideas? we have not triedany thing yet but,werenot getting any codes. I think there may be a little vac leak, but i dont see it. thanks

 

I just thought of something... when the idle problems FIRST started... it would only idle bad if i ran the car hard.

 

Just got back from the dealership. They almost voided my warranty cause one of the guys figured out I had nitrous on the car (damn holes in the trunk... i knew I should have filled them). Anyway, according to them something is shorting out in my "A/C Clutch" circuit. They know FOR SURE... something's wrong with it. Which is what could cause the fluctuationg idle. Next, the guy also said my throttle plate was bent. The only thing I could see that could cause this is once when the nitrous backfired. I've heard of it damaging MAP sensors when it does that also so it could be a possibility. The tech's didn't get finished checking out the car because they found that the car had been modded and could have possibly cause all these problems. But the guy was cool and didn't let them void the warranty. Anyway so now my problem really is either a bent throttle plate, or a fucked up A/C circuit. Today I'm going to try unplugging the a/c compressor to see if that could be the problem. Hope it works because that would isolate the problem to the A/C which would make it much easier to fix. Knowing my shitty *** luck though... it will be something more complicated/expensive/headache-causing.

 

did you fix this problem?

Im having the same exact problem. I replaced and cleaned my old IACV, still no luck.