Hi all,

I've had a frequent code come on, PO440 Evap code. I've had a mechanic check the evap system, the valve thing under the hood clicks on and the valve thing next to the gas tank clicks on whenever he puts his scanner to test it.
Here's the starnge thing, the CEL only comes on when the fuel gage shows 1/4 of a tank of gas. Any ideas?


2002 Cavalier

440 is a large leak in the emissions system, usually 0.040" or larger, this will mostlikely set a small leak code also, you need to smoke the emissions system to find the leak usually.