one last thing with my 98 4cyl auto camry when i start my car any time it idles fine but SOMETIMES when i start it and turn on the ac the rpm is at 1000rpm when its parked then i drive and park again with the ac on its at 750 BUT it doesnt always idle at 1000rpm when i start it. is there somekind of sensor? my mother in law has a 96 trecel with 170,000 miles and the rpm ALWAYS stays a little bit higher with the ac on. whats wrong with my car?

IMHO - Live with it. Be happy. As long as it works, don't fix it.

I strongly agree with Brian R.

When the AC compressor is engaged, the engine will idle faster automatically. Since the compressor cycles on and off to maintain temp., just having the AC button activated doesn't mean the idle will be faster all the time. The only thing that's on all the time will be the radiator fans when AC switch is activated.