I read your problem what l would do first is when this problem starts when it does not crank correctly remove the coil wire this will help to see if this is a mechanical problem or a electric problem. If the trucks cranks correctly than l would look for a timing problem or what ever controls the timing of it still cranks bad after pulling coil wire than l would say that you have a binding problem or cable problem. Also is this truck using a spectrum computer or a est module to control the truck get back to me after you test and maybe we can fix it.