I have a 1998 k1500 5.7 vortec. I had the P0440 evap code occur a few months ago and Ive been trying to fix it ofcourse. So far nothing has worked and it comes back on within a couple days of clearing the code.
All Ive Replaced:
Gas cap
Evap solenoid
Purge valve
Fuel pump
Precat O2 sensors...