Took it to AutoZone and had them put it on the diagnostic machine, it said
the there was a problem with the computer. Took the truck to the
dealership and had them replace brain on the computer,  but the check
engine light still on, checked wires and still did not correct problem.
Took it back to the dealer and they said it may be the GCR Valve, replaced
that and that was not it. Also replaced gas cap and problem still persists.
Not sure how to proceed at this point. I have already spent close to
$1500.00 on parts and labor.  Any help would be greatly appreciated, as my
pockets are just about empty.