2006 CHEVROLET C5500 Suspensionfront Problems

TL*- THE CONTACT OWNS A 2006 CHEVROLET C 5500 WITH A CURRENT ODOMETER READING OF 33700 MILES. THE CONTACT STATED THAT THE VEHICLE HAD FRONT END PROBLEMS. WHEN DRIVING AT SPEEDS 50 MPH OF HIGHER THE VEHICLE VIBRATED AND BOUNCED. THE CONTACT TOOK THE VEHICLE TO THE DEALER 4 TIMES , AND THE DEALER TOOK THE VEHICLE TO A COMMERCIAL TIRE COMPANY, BUT THAT DID NOT RESOLVE THE CAUSE OF THE PROBLEM. *AK THE CONSUMER STATED THE TIRES WERE ROTATED, INSTALLED CASTER SHIN LEFT AND RIGHT, REPLACED DRAG LINK, DRAG LINKED FAULTY, CUSTOMER REPLACED LEFT FRONT TIRE. CONSUMER STATED VEHICLE ALL OVER THE ROAD CANT KEEP STEADY. THE VEHICLE HAD A KNOCK WITH THE #8 AND #4 CYLINDER. THE DEALER REPLACED THE FUEL INJECTED. CUSTOMER STATES FUEL PUMP HAD LEAK AND THE ENGINE SHUT DOWN. DEALER REPLACED THE INJECTOR PUMP, PUMP GEAR AND PUMP BRACKET. CONSUMER STATES ENGINE LIGHT ON,...