09-30-2005, 04:19 PM
I recently replaced a fuel pump on a 97 GMC 1/2 ton 350 pickup. All went well except for one thing. I am having a sound that I can't locate near the top or in the fuel tank. At first I thought the O ring was not sealing the pump mechanism when I placed it back in the tank. After dropping the tank low enough to place my hands all around the fittings and seal I did thorough testing to try to locate this sound. It does sound like air (like a tire leak) so I replaced the vacuumn line but no luck. I simply cannot find a leak anywhere. The is no fuel leaking so I know it is not the pressure side. Also I tried diconnecting the vacuumn line completely and started the truck. Still had the sound. Any ideas? Is it safe to drive it this way?