my car doesn't idle anymore; this started about a week ago.

i cleaned out the IACV. the plugs are fine. it *does* cold idle, and it runs more or less fine except for stalling every time you let off the gas. if you start it and just let it sit for a while, it will manage to idle, and if you very very slowly ease off the gas it will too (although unhappily - it misfires if you try this.)

i took it honda. they looked at some stuff and got confused by all the misc aftermarket electronics and were basically no help.

it looks to me like the TPS, MAP, and O2 sensor signals are just what always were. the dealer thought it might be a grounding problem, but i still think it's the IACV. does anyone have any suggestions? i'm really frustrated.

 

have you tried replacing the iacv?

 

i haven't swapped the iacv, but the dealer claims to have tested it and it is "OK."

here's the update :

it is idling now. i don't know why, but whatever the dealer did or tried to do made some difference. it idles inconsistently and does feel like it wants to stall from time to time, but it is driveable.

BUT

i am now getting a code 304 just about every time i drive. the check engine light will start flashing (misfire) and then it stays on. datalogger reads 304. ALWAYS cylinder 4. the plug in that cylinder looked totally totally frosty white. we switched it with the plug from cylinder 1, and tried again. 304 AGAIN. we checked out the distributor, it looked brand spanking new. damned clean, really. i checked all the connections to the EMS and the ECU and VAFC. all good. checked all the wires to the injectors. all good. moved the ground from the a/f gauge and the ground from the EMS away from the ECU grounds. checked resistance of the plug wires. normal (increasing consistently with longer length).

finally, we stuck a probe onto the injector while running, and while my buddy who is a tech at honda in oakland couldn't hear it, i could distinctly hear, under the sound of rushing fuel, a very consistent "click click click click click." just to verify, we pulled the plug on the injector while it was idling, and sure enough it got pissed off. so the injector is definitely firing. it may be clogged or something, i guess.

the car does not smoke, it seems to drive OK off idle, and it pulls quite hard (DAMN hard, actually, but i have been very hesitant to floor it given the situation).

my vacuum gauge does not read quite what it used to (16-18 instead of 19-21) but we could not find a leak using the "cigarette lighter" method.

what now? what else could affect just one cylinder in this way, and only at low RPMs from what i can tell.

 

well have you checked all vacume s0urces yet... take a vacume gadge to the car.

 

could that really cause a misfire only in one cylinder consistently? how can you check for vacuum leaks with a vacuum gauge?