my jimmy wont start. it died on day and i gave it a commplete tune up. it ran ,somewhat, under hard starts for a week and now it wont run at all. ive bought cap rotor plugs wires and pcv valve and a new cam sensor. ive checked the coil and it is sparking bright and giving good tickle to the wire holder..lol. i checked the fuel pump and filter and all are ok there. they were both changed within the last year anyway. popped open the shrader valve to insure i wasnt vapor locked and im good there. any ideas out there in gmc jiimmy land?