Evening: I currently have a 2006 Chevrolet Silverado 1500, 5.3 engine with 113,000 on the clock. Truck has never been abused and runs fine. Question At full operating temp it developed what sounds like a miss or maybe a exhaust leak last year. Local dealer said it was the belt slapping and the belt was changed but this was not the problem now that temps are getting warmer its a bit louder than last year. Its only noticible under load and easier to hear in the cab than under the hood. Seems to me its on the passenger side. All manifold bolt heads are there and I see no sign of leaks in the exhaust system. Any ideas or does anyone know of something I am over looking? Thanks