weird idle

[sman6452]

I have a 1990 accord coupe with no modifications. When I stop at a light or anywhere for that matter, the engine speed comes down very low. Sometimes down to 300rpm. After a few seconds, the idle comes back up to normal 750 rpm. This happens every time I lift my foot of the accelerator and let the rpm's drop. My car is manual.

I cleaned out the egr passage in the intake manifold but the problem is still there.

Any thoughts on this subject would be appreciated.

[according2me]

I've read the following on other sites as responces to others with your symtoms. Maybe it will help you.

"The idle problem is likely related to the idle control valve system. You should remove the ICV and clean carefully w/ throttle body cleaner, avoiding dousing the solenoid w/ cleaner (could damage the coil wires). Make sure the idle air bypass valve is also working correctly. This can cause cold engine idle problems. "

This valve has different names depending on which service manual you use. Haynes refers to it as IAC (idle air controller) and Honda calls it an EACV I believe. Good luck and heed the warning about getting the cleaner on the coil windings.

Also a good cleaning of the throttlebody would be in order if it hasn't been done in the last 50K.

[princess]

the most common reason is a cruded up throttle body/plate for that year. I think throttle body cleaner has some lubricants in it that "carb" cleaner doesn't & may do a better job in the long run. Much luck!