I own a 2000 Dakota with a MIL on. 1 month ago I replaced the gas cap because the original didn"t pass Pennsylvania Annual State Inspection. Approximately 2 weeks ago the MIL came on. I've had it cleared 4 times since then. Each time the code was :
P0442 Evaporative Emission Control System Leak Detected (small leak)
P0455 Evaporative Emission Control System Leak Detected (Gross leak)

I'm sure I've had the gas cap on tight each time. I've added fuel injector cleaner. And the truck seems to be running fine. Can anyone help me with what I should look at or maybe replace.

 

Hope you get a better response here.

 

personally I'm not very familiar with error codes and stuff. i have the dealer do ti for me. second of all if it is running perfectly fine, why are you worried about emissions. i don't know how Pennsylvania is, but here in Michigan they don't check emission, therefore i would of ignored the emission error code, by not even taking it to the dealer.

 

P0455 is ALMOST always the gas cap... Did you buy yours from the dealer???