Gotta Code, P0440 2002 tahoe

[droppedHoe]

gotta code today while driving to work.
cleared it with the emissions machine but it shows p0440

i know a few other ppl have had this issue on the forum.
i dont have the tighten gas cap msg popping up in the msg center.
but this is the 3rd time it popped up. i saw Anthony's msg about replacing the evap solenoid for only $28 at advanced auto. i can easily get under the truck at work so if this is the case i'll replace it today or tomorrow.

by the way, my truck seems to have lost a lot power...
seafoamed it slowly on tuesday and cleaned the throttle body, replaced the pcv valve yesterday b/c it was filthy. put a new air filter in today...what else should i do?

new plugs and wires were put in 2 weeks ago, ngk platinums

 

[HAYN_HO]

is that the canister that's under the driver seat? i had the check engine light come on the other day went to autozone to reset it and if it came back on i was told to take a look at that and of course the light came back on and all i did was tighten the metal fittings on the canister and the light went off..

my suggestion would be to try that unless you already did.

 

[droppedHoe]

not 100% on the location but i was told it was infront or near the backside of the gas tank