My sister-in-law has a 2001 Chevy Silverado P/U, 4.8 liter, auto. tranny, 2WD & 6.5 ft. bed. I pulled the fuel lines from the filter, cranked the engine over and no fuel from tank. Checked the fuses under the hood and all checked OK. Switched the four pin relay with another from the fuse block. She has not hit any hard bumps. As she was driving her husband to work, the truck acted like it was starving for fuel. When she arrived to her mother's house she turned the engine off. Now it will not start at all. Any other troubleshooting ideas would be helpful prior to dropping the fuel tank.