2007 Chrysler Town and Country engine runs rough only after

I just spent $750 dollars which didn't fix the problem. When ever I put gas int he car, after about 30 seconds, the car sputters and sometimes stalls. Then I start it back up and it runs fine. There are no computer hints, the gas tank was taken off and inspected, the screen for the fuel pump was cleaned, the spark plugs and wires replaced and still the same problem each and everytime I fill it up. It runs better and peppier with a tuneup but still insists on going through this rough running stage immediately after filling up. I have even tried filling up on a quarter of a tank and it still loves to sputter. No one can figure this out.