1999 Dodge RAM 2500-V10 - 8.0L REPAIR ADVICE, PLEASE
Current Problem: Huge (25 second) release of pressure every time I remove the gas cap after driving. Fuel tank likely sucked in. Read following history and tell me what permanent repair is likely needed. THANK YOU.

History:
Sept2011-"Check Engine Code P1481 - Found Fuel Tank Sucked In. There is a restriction. Mechanic blew out evap line on fuel tank and valve opened. Per mechanic, the valve's purpose is to close off evap line should the truck roll over"; 50/50 chance of problem returning; may need new fuel tank.

After that time, there was a strong smell of gas every time I completely filled up the tank (noticed leak stains on side of gas tank), but I didn't smell it when the gas level dropped or when I only partially filled the tank.

May2012 - Brought truck in for repair of gas tank leak - fuel tank gasket and fuel pressure regulator were replaced. Leak seems to be fixed. HOWEVER, I'M BACK TO THE ORIGINAL PROBLEM WITH THE TANK BEING SUCKED IN... AND MY CHECK ENGINE LIGHT CAME ON ONCE AGAIN.