Two problems related to engine knocking noise have been reported for the 2011 Jeep Wrangler. The most recently reported issues are listed below.
Engine failure. While traveling at 75mph on the highway, the vehicle lost power and threw a check engine light. I pulled over to the side of the road and shut off the vehicle and attempted to restart it. The vehicle did not immediately restart, but did so on the second try. I drove away and approximately a mile down the road, the vehicle began to knock and make banging noises, I pulled over once again and called a tow tuck. Vehicle was later diagnosed with failed rod bearings and required a full rebuild. Vehicle had 125k miles at the time of failure.
I started to hear a knocking noise for 3-5 seconds on a cold start. It did not do this on any sequential starts for that day. Took it to the dealer, who changed oil filter and oil. Still made sound on receiving vehicle. Took in again and dealer replaced the lifters. Still made noise upon receipt. Took in for a third time, they are now saying it is a normal noise, even though it never made it before. Jeep specialists say that this is a normal noise as well. After researching on-line, I have found a large amount of information leading to a malfunctioning cylinder head on the exact make and model of my Jeep engine. There have been thousands replaced, but for some reason this was not even considered for my vehicle.