Driving my car back from Colorado to Wisconsin to get the turbo on I decided to drive straight through(17-19 hours). After about 6 hours of straight driving my car would begin stall on the highway. I would push the throttle, but my boost would increase but RPM's would not move at all. After pulling off the highway, I smelled gas inside the car so immediately got out and looked under the hood for any gas residue. While the car was at idle, it was idling at about 200 rpm's(very low and shaky) and sounded like a go cart. Mind this is in the middle of Nebraska so I am very screwed. After an hour on the phone, the car suddenly idles fine and is back to normal. Since this has happened twice with the same result(last time going from Aspen to Boulder) I believe I figued out the problem. My theory is that after driving for such a long time and changing altitude so fast that the gas tank built up enough pressure b/c the gas cap was screwed on that it created a vacuum and fuel wasnt getting to all of my injectors. This would explain all of my problems. Realizing this, I took the gas cap off the rest of the trip and never experienced the problem again. Has anyone else experienced this?

 

Hmm, there is a ventilation valve that should have taken care of this. You might want to have is checked by the dealer. Here's a quote from page 17-12 of the service manual: