Hectic Idle with my 98 Civic DX

My 98 Civic DX Coupe has an idle problam that makes it constantly idle high
then low then high then low and so on as long as the car is running. Can
somebody tell me what the problem is or could be? And is it easy to fix?
Any help would be greatly appreciated. Thanks

 

This is typical of a vacuum leak. When I had the same symptoms I filled
a squirt bottle with rubbing alcohol and sprayed a fine mist of it
around the various parts of the intake system. When I hit the spot where
the leak was, the engine almost stalled.

If that does not help you locate the leak, try pinching the various
vacuum hoses to block air flow. If pinching a particular hose helps,
follow it and see where the leak is (PCV valve, brake booster, etc.)

Some people have reported that if the thermo wax valve (the one that
increases the idle speed when the engine is cold) does not close
properly you can get the type of symptoms you have. You can check this
by removing the air duct from the throttle body. Inside the throttle
body you will find a couple of ports, about 3/8" diameter. Plug each of
them with your finger and see if the problem goes away. If so, you
probably have a bad thermo wax valve (fairly cheap) or (less likely) a
bad IAC (Idle Air Control) valve (expensive).

 

Thanks for the 2nd opinion. My mechanic told me it was the iacv and the
part costs about $250. Do you or anyone else know of any places on the
web where I can buy this and change it myself. I have searched many sites
for it and can not seem to find it anywhere.

 

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Check that your rad is full to the top, and the reservoir should be full
to the 'MIN' line, when the engine is cool.

'Curly'


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Check http://www.hondaautomotiveparts.com/auto/jsp/mws/catdisplay.jsp
Enter the info for your car and scroll down to "Throttle body" in the
"System\component" field.

They are usually a good bit cheaper than dealerships. Still a big enough
chunk of cash that you want to be quite certain the IAC valve is the
problem before buying.