jbailer

It sounds like the cap is not sealing. Are the threads turning smoothly? I can't imagine a plastic cap would mess up the metal threads (it is metal isn't it?). Maybe it's a code from the replacement cap and if you disconnected the battery to clear the code, the light wouldn't come back on. Another way is to just drive it a few more times and see if the light goes away. -Joe

QuickShortBus

It's because the tank isn't sealed, does the factory cap not fit tight any more? If it doesn't then I guess it would be possible he messed up the filler neck. I worked at an Advance Auto when I was in HS and most of the morons at places like that don't know anything. I used to get guys to look up radiators for Super Beetles and they would look for 30 minutes or more to no avail.... I wonder why?

Tik_Tok

I always loved getting the newbies to check the "transmission oil dipstick" on our manual transmission f-350's at my old job.