idel gose up and down car shakes get worse when ac is on when in park idels at 500 rmp or less but when i rev it to 900 vibration gose away some time when driving feels like its gunna shut off i have a 2003 accord ex 2.4

 

Does it do this constantly or is it only at certain times?

Has the Check Engine Light come on? If it has, go to an auto parts store like Autozone, O'reily, etc. and get the trouble code read. Many parts shops don't charge to read the code. Then post the code.

 

constantly the engine light came on one time about six months ago but the next day when i was going to take it too auto zone the light was off i took it any way but it did give any results back

 

Go have them check again right now to see if there are any pending codes. Even if the Check Engine Light is not on, there may be pending code(s) stored.

So, you're saying the idling problem is constant, right?

 

yes idling problem is constant but when its park it not as bad and dose"nt vibrate as much replaced front and rear mounts

 

Have you checked the coolant level in the radiator and the reservoir? Check when the car is cool.

But, check for any pending trouble codes too, which may help narrow down the problem.

Also, is your car an automatic or manual transmission? I'm gathering info. to think about.

 

automatic trans coolant is fine just checked it havent gone any were today so car is cool

 

An idling problem where the idle goes up and down would not be caused by engine mounts. Some Hondas (not just Accords) had problems with the Air Rotary Control Valve (attached to the throttle body) which caused idling problems. The throttle position sensor (TPS) can also cause some of the problems you may be experiencing. A problem with the TPS may turn on the Check Engine Light. A problem with the air rotary control valve may not turn on the Check Engine Light.

Right now, there is nothing to lean more towards either one. My recommendation is still to scan for pending trouble code(s).

On an unrelated side note: There is a Honda technical service bulletin for 2003-2004 4 cylinder automatics for vibration while idling in gear. But, you already replaced the front and rear motor mounts. Motor mounts would not cause the idle to go up and down, just vibrations, etc.