DT*: THE CONTACT STATED THE ENGINE WOULD NOT START AFTER THE VEHICLE WAS PARKED OVERNIGHT. INITIALLY, IT WAS SUSPECTED THE BATTERY WAS DISCHARGED AND THE BATTERY WAS CHARGED FOR TWENTY MINUTES. AFTERWARDS, THE CONTACT ATTEMPTED TO START THE VEHICLE, WITH THE KEY IN THE IGNITION, AND THE INTAKE MANIFOLD EXPLODED. A LARGE FIREBALL ALONG WITH PIECES OF THE INTAKE MANIFOLD AND THE ENGINE COVER SHOT OUT OF THE UNDERHOOD AREA. THE VEHICLE WAS TOWED TO A DEALER FOR INSPECTION. THE DEALER DETERMINED THE BACKFIRING OCCURRED DUE TO THE CONTACT STARTING THE ENGINE WHILE APPLYING THE ACCELERATOR PEDAL. THE MANUFACTURER WAS ALERTED.