NHTSA Complaint #11563525 — 2012 JEEP WRANGLER

In my 2012 Jeep I had to replace the engine and catalytic converters. The engine number 3 cylinder failed due to excessive ware causing lower compression. After the engine (long block) was replaced, one of the cylinders was miss firing. This miss firing was traced to micro cracks in the plastic/composite intake manifold (original and not part of the engine replacement). Because these micro cracks changed the fuel air ratio on specific cylinders by leaning out the cylinders near the cracks this lean mixture would cause the affected cylinders to run hot that would lead to both the excessive ware on the one cylinder and would comprise the catalytic converters. Because this change in fuel air mixture was caused by the intake manifold and Jeep does not have any inspection requirements or methods for this item and even after the Jeep Dealer did a full diagnosis using their factory specified equipment the issue with the manifold was not found. My local AMMCO shop found the cracking in the manifold that was the route cause of the problem.