Get your truck out and go for another drive, if it dies, pull over as fast as you can and get out under the hood to check for fuel in the carburetor. If its dry, you are chasing a fuel problem, if it has fuel, start looking at the ignition.
Suction side of pump is line coming from the tank, pressure side is going to carburetor. A weak pump could cause this when the fuel demand is high, but even a weak pump will keep up with stop and go easy driving. Most pumps work up to the point of death, then they are done, it would be rare for one to be intermittent. The fuel line from the tank is most likely the problem. Its a small opening at the bottom so if anything gets loose in the tank it will end up at the opening. Just to check, loosen the line at the fuel pump (suction side) and let the fuel run into some cans, let the whole tank drain out. You can then re-clean the tank or inspect it better, it would also be a good time to install a temporary filter at the base of the tank. Fuel pumps have very little suction power and don't like to pull fuel through filters so its not really recommended, but in cases like this where you need to check for trash in the line, it will be OK. You can remove it once you are sure its clean.
You said the tank was cleaned and reinstalled, how was it cleaned? The new fuels of today are excellent cleaners and will loosen a lot of trash in a old tank!
Keep us posted, Joe.
