Hello, When I stop at lights, my 5th generation won't necessarily idle at the same RPM. When I am at a stop and it idles at about 700 RPM the engine idle is smooth. Other times when I stop at a light it will idle at a significantly lower RMP (perhaps 400RPM) and the engine will idle rougher. The RPMs don’t fluctuate at a stop however, they stay fixed at i.e. 700RPM or 400RPM. I don’t feel it is outside temperature related. It happens in the winter and summer. Any suggestions for the first things I should try? Thanks!

 

Do you have a 4-cyl or V-6? Auto or manual transmission?

If auto trans, does it depend on stopping with trans in Drive vs. Neutral?

Look at the list of things to check in this thread...
Setting Base Idle speed - Honda Accord Forum - Honda Accord Enthusiast Forums

 

It is a 4 cyl. Thanks for this. I will give this a further look including the drive vs neutral and the checklist and report back.

 

I found the problem. It was the IAC. I tried an Amazon aftermarket IAC, and that made things worse. Surging. What I did to fix this was to take the original and clean it well in an ultrasonic bath. I used about 10% La's Totally Awesome cleaner in water, and I changed the solution until it was no longer dark. Don't let the electronic solenoid part enter the solution. It took about 5 times, but now the idle is very consistent.