I'd done a search and didn't see anything, so I figured this might help someone in the future. I swapped out the fuel filter using Eurothrasher's write-up, it was fantastic. Pretty much any question I came upon was answered in there.

The only issue I had was I tightened the locking ring as much as I could. So I buttoned everything back up and went for a test drive. Within a mile, my CEL came on and the next mile the gas cap light came on.

Well, I went home as I'd run out of time. My kids were getting up and my wife isn't nearly as good at herding as I am. So today I drove it to work as it and the same thing happened. After work I pulled the seat and the access panel off and gave the locking ring a few more hits with the rubber mallet. I was able to get another quarter turn out of it. Problem solved.

Don't be afraid to give it a few good slams to make sure there isn't any room left to go.

 

It always helps to mark where the tape was when you loosened it.... then make sure its gets back to where it was when you tighten it. glad you figured it out

 

Maybe also add your comments to Eurothrasher's thread so people will be aware of this if they just read that thread. Thanks!

 

As it turns out I didn't fix it. After another day of driving after I tightened it, the CEL and Gas Cap Light came back. This morning before work, I had a chance to dive in. I unhooked the fuel line, took off the locking ring, and the think black seal that goes on the outside of the canister was pushed part fo the way into the gas tank. I had a little bit of trouble getting it in cleanly as its circumference seems too big.

So, I lubed it up really well this time and tried to be really careful when I lowered the canister back in. I'm not terribly confident it didn't do the same thing as before with the ease that the cannister popped into place. This job is starting to be a serious PITA.

Has anyone else had problems with that thick black seal?

 

Heres a theory. It could be a completely unrelated vacuum leak. Check all vacuum lines.

 

No, I know it was the thick black seal because when I pryed it up, the seal was partly in the tank. It just seems to big to fit properly in the the hole.