2000 Passat Engine Problems

I have a 2000 Passat, automatic v6, w/ 80,000 miles. The car starts up fine in the morning when cool, and starts up fine if I leave it sitting somewhere for a little while. But, when I travel somewhere on a highway (for about 30 mins) then stop off at a store for about 5 minutes and come back out, the car will not start unless I pump the gas. And sometimes when I do get it started after having pumped the gas, I get a very rough idle and the car sometimes stalls out on me, and I have had to restart the car 7-8 times to get it to finally go and not stall. I find when I move the steering wheel left or right (after pumping the gas to start it) while in park, the rpms drop and has caused the car to stall.

I have taken the car in to the dealership 2 times now and they said that they were not able to figure the probelm from the code they got from the check engine light being on. I also took it into 2 other mechanics, 1 said it was the alternator so I had that rebuilt which made the problem go away for about a month, then it came back. The other place said that Id have to take it to the dealership because they cant read the code they get from the computer, they said that only the dealership could.

If anyone has any ideas about what this could be and how to fix it or if anyone had any similar situations and were able to get it repaired, All advice is welcome. I am at my witts end with this problem.