Okay, so Ive got a 95 bonestock prelude with some idle problems. It consistently bounces from 1k to about 2500. Ive pulled the IACV and FITV off, completely cleaned them and put them back on. No change.

When I unplug the IACV, the idle bounces a lot less violent, but still bounces enough to make the car un-driveable. I know this means I most likely have a bad IACV. Just can't really afford the price oreillys charges for this part and I don't even want to think about what Honda would charge.

Hoping someone knows a temp fix or maybe even a cheaper fix. Anything helps guys.

thanks in advance.

 

when you pulled the fitv off did you take it apart and check to see if it had backed itself off inside? seen it happen too many times

 

nice alliteration...

i had that issue, and it was my FITV. i took it off and filled it with silicone, and the problem was solved. you may not want to do that if you want the FITV to actually do its job.

 

what type of engine do you have i have a fitv off of an f22 if you want it 20 bucks plus shipping I have also seen where low coolant has cause that same problem.

 

A vaccuum leak caused an idling issue exactly like this I had several years ago. Can't remember exactly where though.

 

I had the same problem in my lude i cleaned the carbon build up in the trottle body n changed the tps it then worked fine

 

When I pulled off the FITV, I backed it all the way down and then a quarter turn up. Helped it idle a little lower on initial start, just as soon as I start driving it starts to bounce.

Its an h23, so I'm not too sure that one from an F-series would work.

I'm going to check on that low coolant, because ive heard that air in the system could cause it to do it as well.

The TPS is the sensor on the IACV right?

 

Sounds like way too much air pockets in your coolant. Try bleeding the **** out of it.

 

Same thing with my Prelude, i pulled my IACV off cleaned it and it still did the same thing. i spent like 6 months tampering with things, checking vacume lines and all. come to find out it WAS my IACV and cleaning it wasnt what it needed. So just because you cleaned it out doesnt mean its not the problem.

 

Well when I take my intake off and plug the bottom hole in the throttle body, which I have been told that it leads to the IACV, my idle bounce doesn't change.

Ive bled the coolant system a couple times with no change, but I'm going to bleed it a couple more times to make sure all of the air pockets are out. Turns out i was pretty low on coolant, had to basically fill it up with water/coolant.

Also when I start off and let of the gas, the car will bog down once the RPMs hit 1k and then get really jerky until I give it gas.

 

Vacuum leak. With no throttle input the computer will cut the injectors if the rpms go too high and cause the bounce. If you have covered both holes in the throttle body and no change, its a vac. leak somewhere else.

 

Well when i covered the bottom one there was no change, when I plugged the top one it would almost kill the engine.

Also, its gotten worse..now I have about half the acceleration I did before and it sounds like my car is a lawnmower from idle to about 4k in 1-3rd...

really starting to get my doubts about this car. I would invest in a new one, just dont have the money to do so.

 

Check out this thread, go through all the suggestions in it
and you should be able to sort your problems out. I have
found it very useful in the past, goodluck with it.

https://honda-tech.com/forums/honda-prelude-4/end-all-idle-surge-bounce-etc-problems-thread-1979500/