Start with the easy stuff , check the fuel system and make sure everything is fine there including checking that the valve in the valve cover is working properly , if your pulsing from it , and that everything is clean . If you shake the valve cover and cannot hear it rattle , get a new one . If your still having problems , change the coil , and make sure that none of the wires are loose and possibly grounding out , and don't forget the kill switch , it maybe shorting out . Just some idea's on things to check .