Rep Power: 0

Hello,
I'm having major problems with a low idle on my Honda Civic D17A1. On startup, it idles at 1100-1200, but once warm, it goes down to 750 and then slowly starts dropping to 500 to the point where the car starts to shake and at times will stall.
I've cleaned the IACV valve and my throttle body which didn't seem to be super dirty. I've checked for vacuum leaks in and around the thorttle body and haven't found anything. When I cleaned the throttle body, I did notice an improvement, but 10 minutes later it was bogging down again. I also reset the ECM multiple times.
I recently also had my head gasket replaced. When I talked to the mechanic about the low idle, he said that it was controlled by a computer and there's nothing we could do, aside from adjust the throttle screw(which I don't think is a good idea and just covering it with a bandaid). I went to another mechanic and his theory was that the previous guy didn't recheck the valves(when I spoke to him, he said he did). Now I'm really lost.

Thank you for any help,
Tom

 
Rep Power: 518

You say you reset the ECM multiple times, but did you do an idle relearn?

 
Rep Power: 0

I did the idle relearn according to these instructions:

44. Do the ECM/PCM idle learn procedure.
¡V Make sure all electrical items are turned off.
¡V Start the engine. Hold the engine speed at
3,000 rpm with no load (in Park or Neutral) until
the radiator fan comes on.
¡V Let the engine idle for about 5 minutes with the
throttle fully closed and with all electrical items
off.

 
Rep Power: 179

I changed my pcv valve and it help with low idle at a stop light.

You might want to look into this thread. You are using the wrong relearn procedure, part of it is correct.

https://www.civicforums.com/forums/3...e-posting.html

 
Rep Power: 0

Riceboy mentioned his idle relearn, which is a lot easier to do than the manual's steps:

1) start and drive a few minutes, until engine is at op temp.

2) park and let idle with all electrical loads OFF, for 10 mins or so.

3) profit

The important thing is to get the car to op temp before letting it idle, and not to crack the throttle open, press the brake pedal, or turn anything on during the learning period. 10 vs. 5 mins is to ensure the car still learns despite the cooling fan coming on, as the PCM needs a full 5 mins to do its thing.