Hi people need some help here i have a 2002 civic ex and the idle is really low after it warm up it's not rough or hi and low and no (cel) any ideas on what this could be thanks in advance

 

you could try cleaning out the iac valve on the throttle body or turning the idle screw to allow more air in.

 

I've got the exact same issue. 01 civic ex, low idle, only after the car is warmed up, not high then low, last year it actually stalled a couple of times but only when getting on it after warmed up and then coming to stop.

I've had aftermarket headers installed since i got it back in 2011, a cold air intake, and i've replaced both o2 sensors within the past year or two...so I doubt it's them.

I'm planning on cleaning the throttle body soon and either cleaning or replacing the IAC valve. I've heard (watched EricTheCarGuys video) that cleaning the IAC valve is usually not very effective.