Took a look at hoses connected to vapor cannister
and two vinyl hoses are melted. Not sure what could
cause this but truck has set P0440 intermittently for
about a year. One hose is about 1/4" in dia. other about
3/4" and goes to vent solenoid. Sent request to gmpartsdirect
but not sure if I can avoid getting ripped by dealer prices on
these parts. They seem to be preformed hard plastic hoses.
I doubt that the Napa stores would carry them. The hoses
seem to have been exposed to excessive heat but can't
think of where or when that could have happened. Vehicle
has 60K miles. Any input from experts appreciated.
Thanks,
Fred :confused:

Hi Fred did you ever get the 0440 code to go away? My 2000 GMC is doing the same exact thing. Thanks...........

Hi Fred did you ever get the 0440 code to go away? My 2000 GMC is doing the same exact thing. Thanks...........
Welcome to AF, look at the thread dates before posting, please, this is 4 years old! BTW a loose or poorly sealing gas cap is the first place to look for this code issue.

Never got code figured out. Have gas gauge problem and need to replace fuel pump at some point. Still get P0440 about once a month or so. Clear it and it's ok for several weeks or longer. It's possible it is the filler cap but I don't think so. Once in a while I get a no start and don't know if I hit the gas pedal or not but I need to wait about 10 minutes and then it starts ok.