so for a while i thought i had the p0466 or whatever which was small evap leak
some odb 2 codes can read them wrong and one guy even suggested my truck had the codes backwards according to a repair manual

so i told the guy at the parts counter at gm dealership
bought a gas cap cleared code
a day later cel comes back on

tell parts the light came back on he suggests buying the vent valve so i do
he also talks about how i should notice that the tank isn't being fully pressurized and so when filling the truck up the nozzle will click every few seconds (which it has never done)

replaced the vent valve (didn't do the relocation thing as it was a different part or part of a kit or something)
2 weeks later and the light came on last night

next up is the solenoid i guess?
i also took the truck in to look for a 03-05 cts and they only offered 4k for my truck so
looks like ill be keeping it a little longer or look for something cheaper!
(as gas prices are really hurting right now)