Hello All,

I had the above code in the Buick and have been chasing the cause of it for a few months. Checked the forum and went with the most common fixes. 1) Replaced vapor canister purge valve (check engine light came back on) 2) Replaced canister vent solenoid (check engine light came back on) 3) Replaced fuel pressure sensor and fuel pump "sending unit" gasket (light stays off).

When I took the trunk cover off to replace the fuel tank pressure sensor I noticed a gas smell so I replaced the fuel pump gasket at the same time. I cannot say for sure it if was the sensor or the gasket but because of the odor I am assuming it was a gasket leak because once I put in the new gasket there was no odor even when I overfilled the tank and shook the car. If you have the p0442 code be sure and consider the "fuel tank sending unit gasket".

Have never seen the O-ring leak(original) on a tank.....they leak when they are replaced improperly......

Only sure fire way I know of to detect evap leaks, are with a smoke machine and Tech II....

TTo support your first point the original lock ring showed signs of wear and rough treatment in the past. I replaced it as well.

i would agree its only going to be that if the pump was done and not sealed properly. most of the time on 2000 plus GMs that i have had and worked on is crap in the vent solenoid and seized up. my old mans truck has gotten so bad it took out the wires to it. solenoids dont like being stuck, draws alot of current