Yes, I'm from Texas, and rust is rare. My thoughts were based on the fact that he mentioned he just filled up and then saw a leak. If the fill hose running down to the tank was not secure, it would leak fuel down onto the tank and make it appear as though the leak were coming from the top of the tank. The return line is usually not to dofficult to check either. If it were the pressure line, which I didn't mention, on an EFI truck, this could cause running problems. Keep it basic, check the simple stuff first, then pull the tank if all else fails.
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Richard S.
88 Toy 4x4 Truck, 22RE, 3"BL, 5-Speed, Muds
Proud to be an American. Blessed to be a Texan!