I have a 2002 ram with the 4.7, Its the first Dodge I've ever owned and love this truck. My biggest problem is this P0440 codeI replaced the fuel cap, reset the code and it came back on after a few days of running. I inspected the lines at the canister and seen no big problems. Is there anything I might be missing, is there a specific problem area I need to be looking at? I not too sure about the "purge canister" under the cab. Could this be the problem? Any help will be greatly appreciated.

 

You should double check the vacuum line from the throttle body to the purge solenoid. Double check the lines for leaks. The best way is with a smoke machine. There could also be an issue with the purge solenoid or the electrical connection to it.

 

I double checked all the vacuum lines from the canister and the back of the maniflod. I stumbled accross a small crack in one and changed it out, so far so good...no code...thanks for the advice.....