Ok, noob here with a couple of questions. I just bought my wife a 91 Honda Accord so that she would have something to drive that had AC. Well, the car has the (in)famous hunting or surging idle issue. In Park or Neutral, it will go from about 1000-1500 rpms. I did my homework (i thought) and read about the FITV valve needing to be tightened (unscrewing the cap, tightening the ring inside). I did that, no change. I then read the that Idle Control Valve needs to be cleaned out with brake cleaner. Did that, no change. Then my brother in law tried something: he disconnected the ICV, and the hunting stopped, dropped down to about 950 rpms and just purred there. But then the check engine light comes on. So i bought another ICV (used), and there is still no change. I know it has something to do with the ICV, but I don't know what, as it does the same thing with a different one. I guess the one i bought could be bad, too, but that doesn't seem overly likely. Does anyone else have any ideas? A mechanic that glanced at it said it could be a head gasket issue. Any assistance would be appreciated!!

 

Good chance it's an air leak. Buy some parts cleaner from autozone and spray around the vacuum hoses and intake gaskets. If the idle suddenly acts weird when you spray a certain spot, you found your problem

 

you were almost there. but this could help.

setting idle speed,

let motor get to running tempeture,

while the motor is running disconnect the iacv. (rpms will drop to its lowest point possible)

with the motor still running,

head over to throttle body. you will see a flat head screw right near the top of the thottle body. in some cases it might be covered with a plug, just pry out the plug to expose the screw.

now with this screw adjust your rpms to 700rpms. i believe turning clockwise is to lower and counter clockwise to raise the rpms.

now you have the correct idle speed. but wait!

connect the aicv back in and turn the car OFF. go to the fuse box on passenger side(under the hood) and take out the 7.5 radio/back up fuse for 20 seconds and put it back in.

now your idle should be reset at 700ish rmps.


.....if this fails, bleed the coolant. if that fails check for vacuum leaks with carb cleaner or propane.


GL

 

And on this gen - there is the air boost valve on the drivers end of the tb.

Check for vac leaks, don't forget to check the PCV valve and hose.