Ok, I'm lost... I have an 07 H2 with a new canister and gas cap that throws an error "tighten gas cap" within the 1st mile or 3 min only from a cold start. Throughout the rest of the day it's never mentioned again Help!

 

did you replace the purge solenoid as well? check the filler neck at the gas cap for rust as well, maybe it is not sealing properly. you can try clean it up with some sand paper or steel wool or scotch pad.
but it can also be pinholes in the filer neck tube or pinholes on your fuel pump.
also make sure whatever hoses you disconnected are fully seated when the parts where changed

 

Thank you. I'll check into it and let you know.