I was in the middle of a new reply and managed to erase it, so here goes again:

My new service rep called today and said a rep was flying out to SD tomorrow to look at my car.

TerryXfire - I think the real issue with overfilling the tank is that excess gas will overflow into the carbon canister and ruin the carbon. In case all of this is new to you, there is a container filled with carbon that is connected to the gas tank. The idea here is that gas vapors will be held by the carbon instead of getting into the air. These vapors will eventually be routed to the engine. If you download the service manual there is a good illustration of all of this. I believe our Crossfires are OK to overfill since there is no warning in the owner's manual. And welcome to the forum.

Matt - It took about two weeks for the supercharger to come in. It took another 4 days or so to get it installed. Mike actually called me and said the installation was far more involved then they originally supposed.

AMGlover - 1. Up to now I've been thinking that the problem was venting related because of the tank already being changed out. But the symptom really does support a stuck check valve in the filler neck.

2. I've had the car to at least two different stations and have used a number of pumps so the problem is not pump related.

3. I don't really jam the nozzle in, but I do shift it around to see if that makes a difference. It doesn't. One thing I've noticed is that after having the new tank installed, the filler neck can be moved around a tad. I never noticed that before, but then again I wasn't shifting the nozzle around before either. Can anyone else get their filler neck to move a little bit?

4. This sounds like a variation of ghostriding.

Excellent suggestion with the garden hose. I'll see if I can talk to the rep and get him (or her) to try this. If the rep is not game then I'll get my car back and try it myself.