93 civic idle issue after car heats up
 

Idle becomes very random after car heats up. Let the car run for about 25 minutes to warm up at idle then held rms at 3000 for about 20 seconds and thats when the idle start fluctuating between about 1500 and 2500 rpms. I bled the coolant system, cleaned IAC valve, change fuel filter, change thermostat, all new plugs, cap, rotor, wires. This started after I clean the IAC valve and reset the idle. I dont know where to go next to fix this problem. help?