ok i have a 1997 v6 auto trans car will start i can run it for awhile, (sometime stalls at a stop/in park) ill take it somewhere let it sit for a half hour nd if go to start it all it does is crank so i sink the gas to the floor then it starts up but if it sits say over night it'll start right up! i replaced coils,fuel filter,battery. what could b causing this is it the fuel pump? crankshaft position sensor?

 

Check engine lamp lit? do you get black smoke from the exhaust right after engine is restarted?

Sounds like an injector may be leaking and flooding engine when engine is stopped. The reason it is OK after sitting overnight, is that the excess fuel has either evaporated or drained into the oil pan. Check fuel pressure with a gage right after engine is stopped, if the pressure drops while looking, an injector may be leaking..

 

as far as black smoke i havent noticed any. once in awhile it will stall if its been runing for say 30min, and i come to light,stop,or even if i put in park in the drive, way when this happens the check engine light will come on other wise nothing during nomal operation.

 

May also want to check the IAC valve, bad ones can do strange things to idle speed. I don't guarantee that this is the problem but it is possible. Also check the fittings for the EGR, the tubing can crack due to the age and heat and feed good air instead of exhaust to the engine and confuse the PCM resulting in random stalling. Had this happen on a very old Grand Prix, and had a good old time figuring it out.