My idle started fluctuating a couple weeks ago, ranging between 1500 and 2500, hot or cold, doesn't matter.. its really hard to drive because the car wants to pull hard when my foot is not on the gas. I read a bunch of threads here and tried just about everything i think. the upper throttle body port is pulling in a lot of air, so much that it makes a suction noise that is far from ordinary, and the throttle is closed all the way

i've thus far replaced the iacv, fast idle thermo valve, pcv valve, cleaned the throttle body and idle screw ports, sprayed carb cleaner over the vac lines to test for a leak and still nada... any ideas? I did notice that there seems to be a lot of pressure in the coolant lines that run into the iacv and fitv, and they seem to be dripping at the points where the tubes meet the metal bends. there are no clamps on them as of yet, but there never were before, and this dripping is new. could my thermostat housing be clogged? and would this perhaps cause an idle issue? my only other thought is that the ecu is toast... please, any help would be greatly appreciated. thanks in advance.

any ideas? thanks in advance.

EDIT: Forgot to mention I have a 95 VTEC

 

I had this same problem in my old 87 crx si many years ago. It went away when I bled the coolant. Not sure why, but that worked for me. I noticed there was coolant running through one hose and none in the other. There was a bleeder screw on that engine if I remember correctly. A ton of air came out and the idle stopped hunting and I never had another problem

 

its not your ecu, so don't even look/touch it.
Probably a vacuum leak somewhere.

you've replaced everything else, (which were probably all still good anyway), so the only thing left, (and what was probably the problem from the start) is a vacuum leak.

Do you have any aftermarket/performanc* parts on your car? CAI ect?

 

I have an CAI, thats about it in there... How can u be so sure of the ecu? Ill try the carb cleaner trick again... i also tried bleeding the coolant, and i'm not sure how long to do it for... i realize that you're supposed to do it till air stops coming out, but all it does it flow and then stops along with the fluctuation...


Modified by neldogg at 3:03 PM 11/11/2007

 

the procedure to bleed a coolant system is to fill the radiator till the top. Then open the bleed valve until you get a steady stream of coolant, with no air bubbles at all. Close the bleeder valve. Then run the car with the radiator cap off (heater all the way on) until the car gets warm and the thermostat opens and you see coolant flowing by the ripples on the top surface. If coolant drops from the rad, then add until it stabilizes. Replace the cap, and you should be good.

Maybe you could test the relation of your idle to your ecu by warming the car up, then turning it off and jumping the code pin terminal in the cabin. I might be wrong, but with that terminal jumped, the car runs in 'limp' mode and the ecu doesn't really take data and make changes. Its more like the car just runs in the safest most conservative setting, with no ecu input on things like ignition timing (which is rough in that mode), and perhaps idle. So if your idle stabilizes with the pins jumped, than it looks like a sensor/ecu issue. If your idle still oscillates, then it would seem more like a vacuum/physical air flow issue.

hope this helps. good luck.

 

so it turned out to be the starting air valve, i guess it just broke... lame..