My 1998 civic ex auto has 148,000 mi. and lately has been idling very low when warmed up, just enough not to stall. When I turn the lights on, the idle goes up a bit makes it more tolerable. I searched a bit and was convinced my IACV needed to be cleaned. I took it apart, cleaned it, and reassembled. Car still does the same thing, possibly even closer to stall now. I haven't had any CEL (besides the one I got when I unplugged the IACV plug while the car was running to see if the idle increased, which it did). I have not noticed any vacuum leaks, but does't mean they don't exist. What do I check next? O2 sensor possibly? Any other valves or sensors? Car runs great at cruising speed - only at stop light does it idle just above stall.

 

You'll find a diagram in the FAQs sticky (D16Y8/auto transmission) describing how to adjust the idle speed. Follow the directions exactly.

 

Thanks. I saw that in the service manual, but the general concensus seemd to be that adjusting the screw is a bandaid fix for a bigger problem. However, I did turn the screw and the idle seemed to change momentarily then work its way back down again. Each direction I turned it, the computer acted like it compensated and brought it back to where the idle originally started. Does this sound wierd?

 

General consensus? Not sure of your sources or the number. You'll find bad information all over the internet.

Did you follow the instructions in the diagram? What is the condition of your spark plugs? Is the ignition timing set to spec? Is the PCV valve or hose clogged? Did you connect a tachometer? Did you warm up the engine? What was your idle speed at the end of step 3? How many revolutions did you turn the screw by the end of step 5? What was the final idle speed?

How did you clean the IACV? What did you clean?