Have Jeep Questions? Ask a Jeep Repair Expert for Answers
A single bent valve wouldn't cause an engine not to start, on the same vein as a muffler installed backwards should not cause an engine to backfire or bend valves. Why was the original muffler replaced?
Most importantly, what vehicle are we working on? Year, make, model, engine size, gas or diesel, auto or stick, 2 or 4WD?