i was driving my 93 camaro z28 when all of a sudden it just died. right befor it died it made some sort of backfire noise i cant exactly describe it because it happened so fast. when i tried to start it it made a simmilar noise to when my opti went out. i have no spark. since then ive changed the opti, coil, and modualr thing next to the coil. any ideas as to where to look from this point ?