[matt67350]

What are you running? V8, L6, or any other motor? You should check your timing and see if you have fire to the # 1 cylinder. That goes for any motor you have. Do you hear a knock when you try to crank the motor. Pull the valve cover and see if the valves are moving, also check for a bent pushrods.
For V8 pull the driverside valve cover. Good luck.
Matthew