I have an 89 Ford F250 4x4 with the 4.9L engine 5 speed manual and dual tanks. The truck died and will not start. It set for a day and started and was able to move it about a 100 feet before it died again and will not start at all. The pumps are working in both tanks and on frame rail. I removed the fuel line after the fuel filter and turned the pumps on and fill a quart jug in seconds with clean gas. The pressure valve at fuel rail will shoot gas over the fender when depressed. I have also checked the relays and they are working. It is getting spark thru the coil and plugs. I can shoot some starting fluid in and it will fire but still wont run. I also tried to pull start the truck and it won't run. I have also checked the wiring and fuse links and found no problems.
If any body has had the same problem please let me know, this thing is driving me nuts and I have hay I need to move.  

First thanks to everybody that took time to try to help with my trucks problem. I didn't imagine 30 people would check it out in one day.
The problem was my starter was loose. The ground from the battery also goes to one of these bolts. Once I tightened the 2 bolts the truck fired up. I guess this is proof to not over think things when tring to diagnos a problem.