I took my 98 2.5L contour to the dealer after seeing the check engine light.

I assumed it might be the gas cap. My wife didn't screw it on all the way and this gas cap has become extremely difficult to put on. I don't know if it is stripped or what but it takes me a good 5-10 minutes to get it on. Its a physical issue.

The dealer got a P0455 code told me the vent valve and i believe solenoid (i might be mistating this) had to be replaced at a cost of $950.

I asked him if a P0455 could be set off by a bad gas cap or a lack of seal there. He said P0455 has nothing to do with it, which contradicts what i've read here. He told me they couldn't even reset the CEL light.

I got home and checked out the gas cap. it was barely on (not my doing though i did tell them to check it). I've ordered a new gas cap and took my car but I'm wondering if i can trust this dealer.

I am also wondering if the thing the gas cap screws into can be replaced in case the new cap still has problems going in.

Thanks. Any help appreciated.