TL*THE CONTACT OWNS A 2008 FORD F-450. THE CONTACT STATED THAT THE FUEL PUMP IS CAUSING THE VEHICLE TO JERK AND SMOKE. THE PUMP HAS BEEN REPLACED TWICE. WHEN THE VEHICLE WAS REPAIRED THE FIRST TIME, THE WELDING NUT WAS BROKEN. CURRENTLY, THE VEHICLE IS BEING HELD TOGETHER BY THE NUTS AND BOLTS. FORD STATED THAT NOTHING COULD BE DONE BECAUSE COMMERCIAL VEHICLES ARE NOT COVERED UNDER WARRANTY. THE FAILURE MILEAGE WAS 16,000 AND CURRENT MILEAGE WAS 19,000.