I have a 2.2L '96 Cavalier that had a leaking fuel injector and fuel pressure regulator. I replaced both parts and then took it to a mechanic to double check things and to clear the codes. As for the codes he said there were a bunch of them so he cleared them out, and told me to bring it back if the check engine light came back on (since he didn't know what I've fixed / tinkered on.

Well the check engine light came back on, but I decided to just buy my own scanner. The code is PO440 Evap Emission Control System Malfunction. I've heard this is commonly associated with a loose gas cap. If that's not the problem, what else could it be and what should I check for?

Thank you in advance...
Alex

 

Check for the smell of gas...

Vapor pressure sensor malfunction...
Fuel Cap cracked or loose (already checked)
Vacuum hose blocked, cracked, torn or disconnected
Hose or tube blocked, cracked, torn or disconnected
Fuel tank damaged

that sort of thing