trouble starting

It sounds like you have a bad connection at the battery. One of the battery cables may be corroded internally, or bad in some other way. The next time it won't start, try wiggling the battery cables one at a time while someone tries to start the truck. This will help isolate a loose or bad battery cable. Also look for a loose connection where the negative battery cable connects to the engine block or frame. Loose battery wires are VERY often the cause of a no-start situation. It is possible that by removing and re-attaching the cable at the battery, you move it enough to regain connection on the other end.