03-22-11, 11:41 AM
I have a 2005 STS with a V6 engine. When the fuel tank is a 1/4 tank or less and I fill it up, the car will sometimes shut off if it is running while I am fueling. If I turn the car off and fuel up, I have to leave the gas cap off to start the car. If the cap is on, the car will not start. Is this a fuel pump problem or a fuel pressure regulator problem? The car also idles very rough but runs fine as soon as I get to 900 rpm or higher.