TL*THE CONTACT OWNS A 2005 PORSCHE CAYENNE. THE CONTACT STATED WHILE DRIVING AT LOW AND HIGH SPEEDS THE VEHICLE LUNGED FORWARD. HE ALSO HEARD A LOUD NOISE IN THE ENGINE. THE VEHICLE WAS INSPECTED BY A DEALER WHO ADVISED HIM THAT THE IGNITION COIL AND CYLINDER NUMBER 5 NEEDED TO BE REPLACED. THE IGNITION COIL WAS REPAIRED; HOWEVER, IMMEDIATELY AFTER LEAVING THE DEALER THE FAILURE RECURRED. THE DEALER WAS CONTACTED AND ADVISED HIM TO BRING THE VEHICLE BACK. THE FAILURE MILEAGE WAS APPROXIMATELY 66,000. THE VIN WAS UNAVAILABLE.