What a royal pain! Those bottom bolts are hard to get to...I thought I was going to have to remove the fuel rail. Cleaned the Idle Air Control Valve last night, will put it on this morning. Hope it helps the bucking problem that occurs when operating temp is reach.

 

cool. Post if you are still having problems.

 

I cleaned even though it looked like new. Took off the throttle body to reinstall. Should have done that to begin with, but was reluctant as this is my first Honda. Unfortunately it did not fix the problem. Will order one for replacement. Do I need to reset the check engine light to tell the ECM that the valve is new/clean?

 

Reset the CEL. Tell us what code comes back on.

Surging idle can be a number of things. You should start off by telling us what motor you have (year make model trim helps too) so we know what you are working with exactly.

Vacuum leaks, FITV issues, timing, IACV issues, and more can cause the idle to go up and down. You say that the problem ONLY happens once the car is warmed up 100%?

 

If it's misfiring in gear mostly when you push the gas hard at low rpm, that sounds like typical weak sparks. It would not be an IACV problem. The IACV is only important for idling and when you first try to take off without pressing the gas.

 

My Civic is a 1998 DX w/ D16 Y7 motor & manual trans. The sympton is it bucks when feathering the accelerator in traffic. Sort of like being in too high of a gear, but only upon depressing the accelerator. The code is for the IAC. Maybe a vacum leak instead. Should I just replace the vacum hoses?

Thanks,
Tommy

 

Has it ever worked properly since you had the car? You could have the wrong ECU if someone before you was swapping parts. Otherwise you will probably need to replace your IACV. It can be checked with an ohmmeter but I don't know the spec for the 3 wire one.

 

is there a dongle on you firewall that has a couple vacuum lines that go to it?

 

Not sure what a dongle is. A new IAC valve did not solve the high idle or the bucking when feathering the accelerator. I'm not sure I know where all the vacum lines are but I have a diagram (more like hieroglyphics). I don't think this D16 Y7 has a FITV

Do I need to reset the engine light or will the ECM acclimate?

 

So you still get the IAC code with a new one? That suggests mismatched ECU or a wiring problem. Again I ask did it just start doing this, or has it never worked right since you've owned the car?