hi,my name is XXXXX XXXXX I will help you .
has anyone checked the ground wires to the motor ,as in , the main ground wire from the battery to the motor and as well the ground to the starter,I have seen grounds run from the frame to the bolt to the starter .does this kind of hesitate /chug when you are trying to crank over the motor when it is hot ?
when it does start after cooling, it does lug as you suggest, cranks very slowly, and may not fire until it is cooler, it takes such a power drain, that starting it too soon may kill the battery and require a jump. The vehicle is currently in the shop so I am unsure of the ground set up, but I believe it runs to the frame, and then on to the starter. How would this result in the system being hot when the engine is hot, and cold when the engine is cold?
when i went through schooling I was taught that you never can have enough grounds.but if the ground is bad ,because the starting system takes a lot of amps to start the truck and if the ground path is bad /loose/corroded it will create a higher amperage to start the vehicle thus it may burn up other components in the process,esp.when its hot the motor is tighter .
it is best to measure the voltage (positive) as well ,.
I would check all grounds for being clean and tight .check the ground voltage ,when crankng the motor over hot ,the chugging points to a ground issue ,as an added point if the positive is not up to par 12.5 volts-13.5 this too may cause higher amperage to start the vehicle .
so ,check the grounds(if possible run a ground from the frame to the starter ) also check for 12.5 -13.5 volts to the soleniod when cranking it over hot ..jazzmaster ..