Quick question. ON my 2006 Silverado I had a 3in exhaust from the cat back. It was fine for 4 years and then the muffler and tail pipe rusted out. Being unable to get the stock exhaust out of storage I put a 3" single inlet and single outlet muffler and a 12" stretch of pipe with a turndown on the end of it. I had this stuff hanging around so I am keeping it ghetto temporarily. When I down shift or even get the revs up over 2500 then hit the clutch to shift, or just slow the truck down with a higher gear the exhaust pops constantly. What causes the popping? Can this cause engine damage?