P0440 EVAP code, need help

This has been an ongoing problem for quite some time now. I keep getting a P0440 code from my ODB. I tried all the easy stuff, new gas cap, checking lines and fittings, but I still get that code every now and then. It seems to rear it's ugly head when I have driven somewhere, ran in and then come out and restarted the truck warm. More so if has been raining or it is damp outside and if I have a under a half tank of gas.

Any ideas of where I should start? I'd hate to just start throwing money at the problem. So, if somebody has a good guess as to where I should start, let me know.


Thanks

mine or anyones best guess is to take it to a garage and the mechanic will fix it or trde it in if it cant be fixed

Take it to someone that has a smoke machine and they do work finding evap leaks.The smoke starts coming out when the evap leak is found Under the hood there is an evap line with a connction,green cap with a a label saying for evap

Look through this Link (http://gearchatter.com/viewtopic9008.php?sid=2068f63a39a33b765dddbd4d4c38 aab7)