I have a Pontiac Grand Prix 03 and when you
go to take off it starts jerking and shaking
really bad until you get up speed then it
slacks up and starts back when you mash
the gas pedal. Also if I stop for a few
minutes it starts to run hot . What could be
causing this???? PLEASE HELP!!!!!!
Seems like two separate problems. The shaking is likely caused by an ignition problem. How long has it been since anything has been serviced? (plugs, wires, dist cap & rotor, timing, fuel injectors, fuel filter, etc.) As for your cooling problem, could be water pump, system clogged, radiator or heater clogged, low coolant level, cooling fan not working, etc. Many possibilities. Troubleshooting needed to determine the cause.