VEHICLE WAS APPROACHING TRAFFIC LIGHT WHEN INCURRED A SURGE IN ACCELERATION. DRIVER APPLIED BRAKES BUT ALSO HAD TO SHIFT TO NEUTRAL TO AVOID HITTING OTHER VEHICLE. DROVE VEHICLE .7 MILES BY SHIFTING BETWEEN DRIVE AND NEUTRAL WITH ENGINE AT HIGH RPM. TURNED ENGINE OFF AND THEN PLUG WIRES AND WIRING HARNESS BURST INTO FLAMES.