Why does my 1994 Honda Accord LX act up when I'ts. Warmed up?

Runs fine till its warm. But dosent always act. But it does a lot. Has got too be in a fuel delivery end of things. But I really don't know, Hence the Q,& A. So MOTOR HEADS OR TRCH GUYS/Gals or any one. I'm stumped I'm. Idol control valve is what I'm guessing. Any one did thanks in the. M

Judging by the mention of the IAC valve I assume the idle is hunting when warm. The most common cause of that is a bubble in the coolant - the Fast Idle Thermo Valve does not get hot coolant at idle so it opens, raising the idle enough to get hot coolant to it and close the valve, dropping the idle… There's a bleed nipple on the housing where the upper radiator hose connects to the engine. When the engine is cool, open the nipple 1/2 turn and close it when a steady stream of coolant comes out. This must be done any time the coolant is drained and refilled.

Other potential causes include a vacuum leak. The IAC often gets involved in the dance so unplugging it may change things, but I have never seen the IAC be the cause.

FlagMichael is corrected. Your Accord acting up in "closed loop" meaning the car runs within a "Preset" parameters from the factory into the PCM so when the engine is up to the operating temperature, all of the sensors input to the PCM and the PCM "react" accordingly to those inputs.

You'll need to find out which sensor or input that is defected or out of range making your engine "Act up" whatever you've meant.