[81_Bluestreak]

When i start my car after it 've been warm up, it idle real rough, If i step on the gas pedal to raise the rpm to about 2000rpm then let go of the gas it idle just fine. It idle fine in the morning when the engine is cold. I already replaced the AAC Valve, Cylinder Head Temp. Sensor, Spark Plug, Wire, Cap and Rotor, Exhuast manifold Gasket. There is no vaccum leak. All injectors working fine too. What else could I check for? Thanks for all your help.

 

[TurboSi]

Once again, what car, what year, what engine?

 

[81_Bluestreak]

Sorry guys! It 's an 81 280zx turbo.

 

[TurboSi]

Small suggestion

After you start the car when warm and while it is idling rough, cut it off and pull the plugs for a look to see if one is fouled. Got the proper heat range plugs? Might want to consider one step hotter (one number lower for the NGK's). I run NGK 5's instead of the 6's in my '81, for instance. Plus, even some new plugs are faulty. At least you may be able to determine what cylinder is causing the problem. Also, you should do a compression check to verify that all cylinders are approximately the same, give or take 3 or 4 pounds.