My Gas cap light went on and won't shut off? I checked the cap and it appears fine.
And just yesterday the Check Engine light went on...............any thoughts?

Thanks,
Mark

 

Gas caps aren't too expensive. Maybe you can buy a new one and see if that relieves the problem. If you don't have a locking one, maybe a good time to get one of those. Let us know what you find or do.

 

Before buying or replacing anything, get your codes read.

It might be the cap or the cap's seal. The cap must seal properly in order for the evaporative emissions system to work properly. If the seal is okay and the cap was properly installed, then try a replacement cap (get the proper type). If the fault persists even after replacing the cap, then there's an air leak into the system. Dealerships and some independent shops will have a "smoke machine" that will make it easy to pinpoint any evap system leaks.

Steve

 

you've probably tried this... but just in case...

have you given it a good spin after its tight? (so it clicks around) I heard one time that if you don't get it to click at least 3-4 times it will not register as tight.

 

This happened to my girlfriend's 2005 F150 XLT. She bought a new gas cap and that did not fix the problem. Believe it or not, there was a crack in the fuel pump, and that's what was causing the problem! If the new gas cap doesn't work, take your truck and have the fuel pump checked over.

 

Before you go out and buy any new parts, get somebody with a code reader to check your truck. Leaving your gas cap off will kick a code and lead to that light. If I recall correctly though, simply screwing your cap - or a new one for that matter - back in will not reset the code immediately. I believe it takes several driving cycles to reset.