4 Wheel Drive/SUVs: 2003 Nissan Pathfinder fuel problems, nissan pathfinder, radiator shop

Question
I have a 2003 Nissan Pathfinder. Two months ago I had the catalytic converter replaced due to a crack. Since that time my engine light has been coming on. Now, I have a vapor problem in my gas tank and the pump shuts off after putting in four dollars worth of gas. I can fill up the tank but it takes me quite a while.  I took it to a mechanic and he blew all of the lines out and the problem is better, but its still a problem and the engine light is still on. Now the mechanic wants to  replace the gas tank.
Any suggestions before I stick over $500 dollars into my vehicle?
Thank You
Char Schweich

Answer
There is a rollover valve inside the neck of the gas tank that prevents gas from running out of the tabk in the event of a rollover. This valve can fall and get stuck causing the gas tank not to vent properly setting off the check engine light. This valve may be replacable so check into it before dropping the cash for a whole tank. Chck junk yards too. If you find one take it to a radiator shop and have it cleaned, they will boil it out with caustic cleaner used to clean radiators and it will be like new

Matt