Tony,
I have put fuel pumps in a solvent tank and operated them manually..the fuel blew out a good four inches or so. If there were a restriction in your fuel tank, your clear plastic line to the carburetor would be full of fuel, but it wouldn't be moving. If the pump isn't pushing fuel, the discharge side would be full, but no pressure.
I'll bet the see through hunk of fuel line is just a troubleshooting device. Don't forget to remove it lest it melt or break and barbecue your truck.
If it's a fuel starvation issue, it usually takes a little time after it fizzles out for it to restart. If the engine craps out, then you can instantly restart it, you are out of the fuel arena and into the electrical/loose wire/ignition scenario.
Stuart
