JIM5.0

Yep, no gas cap. But that does not mean that the capless receptacle is not damaged in one way or another and thus cannot keep vapors from escaping.

A major reason why you should never forget to put the gas handle back onto the pump. The force of the gas spigot still in the receptacle could be more than powerful enough to do some serious damage.

darinhebert

well, this is what i found. i put a bottle of octan boost in the fuel the other day. checked the gas cap and it was not in the locked position. poked at it and it shut properly. cheked the lines on intake, they were all connected. i cleared the codes and will see what happens. thanks for the info...

Napoleon85

By gas cap, I assume you mean fuel filler door? If it was partially open, that would make the code pop up. It's the equivalent of having the gas cap off.

darinhebert

yes, filler cap door. no gas cap. cleared the codes. the wife has not called or texted me that the engine light was back on....first Mustang, and gotta say that new 5.0 is fun to drive........thanks for the help everyone......