HAVING PROBLEMS WITH '93 PREVIA....REVERSE DOESN'T WANT TO WORK AFTER CAR HAS BEEN RUNNING..WHEN ITS COLD IT WORKS FINE BUT AFTER ITS BEEN RUNNING A WHILE I HAVE TO GIVE IT A LOT OF GAS TO MOVE IT IN REVERSE AND THEN IT ONLY MOVES ABOUT A FOOT AT A TIME AND WHEN IT PAUSE THE VAN REBOUNDS FORWARD LIKE I'VE SLAMMED ON THE BRAKES....ANY IDEA WHAT THE PROBLEM IS....WOULD LIKE TO HAVE AN IDEA BEFORE I TOOK IT TO THE MECHANIC...THX