I bought a used 93 civic DX It runs great but after it warms up and you turn on the A/C and/or the lights the engine idle drops and the oil light flickers. You Can barely give it gas and the light will go out. I've replaced the oil sensor and put a new distributor and rotor button on it due to the cap had cracks inside at the probes thought that might have something to due with the drop in idle but it doesn't make any noise what so ever.

 

I would guess that the idle is set a little too low. Verify (with a timing light) that the ignition timing is spot on, then set your idle speed.

 

Any CEL codes? Click CEL link in my signature.

Sounds like a low idle problem. Clean the IACV -- click link in my signature -- and also replace the PCV valve. Report back if the idle speed remains low.

 

Replaced the pcv valve and cleaned iacv valve it runs even better till you turn on the a/c or the lights. Now it is idling erratically. I'm confused was going to check the codes but can't find the plug under kick panel. ecm is there but I found a plug under the dash just above it one side is gray the other brown that may be it. Thank You for your response.

 

The test plug you want is the one with two wires. The one with 3 wires is used only with Honda proprietary test equipment.

Does the A/C work OK? If the condenser fan doesn't work, the compressor will build up excessive pressure which causes it to bog down the engine. Assuming it's not that, you could try opening the air screw on the top of the throttle body to get more power at idle for the A/C. Open it too far though and it will idle too fast with the A/C off.

 

The service connector is above the ECU. It may be plugged into a rubber holder.

 

Thanks again for the info. I found the plug and checked for codes but no luck there was none. Cleaned the FITV also thought that might help but no change. I also checked the fans make sure both were kicking on and they are. The A/C blows good cold air. It just pulls they engine down when you turn it on. Looked at the Haynes Manual and it said to check the EGR valve but it's not there. Can you plumb it up and by-pass it? Thanks again for all your help hopefully soon we can figure out what's wrong.