my CEL comes on with the code for bad gas cap, i reset by disconnecting bat and is fine for bout 200 miles then it comes on again? any ideas? i think i remember reading something bout the gas filler tube, but mine doesnt look that bad?

I'm gonna take a shot in the dark, but maybe its the gas cap

track it and see if is associated with buying gas, or gas tank half full or what ever. or jus buy a gas cap.

Are these systems so precise they can detect that it is a gas cap or just a fuel pressure problem.I know on alot of vehicles,domestic and foreign, not tightening the gas cap will throw a emission code,tighten the gas cap and the code or CEL light clears itself.Just curious??? John

its a new cap so i dunno

There are a whole host of things that can go wrong with the evap emissions system, if your new cap is sealing, its something else either leaking, or the solenoid isn't venting properly, either way, i'd take it into the dealership and have them put the gas generator up to it so they can identify the leak, or failed component. A good reason to get this fixed is because you don't want a more insidious engine code to be hidden while the evap system is shot.