OBD Code 0442 Means ...

[LBJ]

2004 Silverado 5.3 V8.

... that your gas cap is not fully screwed down. Ha. Had a check engine warning light come on and read the code after I got home. "Evap System Leak (small)." Called my mechanic and he said it was likely the gas cap. I screwed it on tight and will see if the warning light comes on again. Almost a nuisance message. Maybe it has deeper meanings like the gas tank has to be sealed or something else will happen, more serious. I drove for almost one hour to get back home with the warning light and the truck ran fine. So, no big deal this time.