I have been having ECM gremlins since the build was complete and rolling under the L86 power. The Jeep has been running rough, shifting hard and getting terrible fuel economy for about six months. The state inspection is coming due and the problems have been triggering the fun check engine light. I have known about the check engine light for a while, but mostly because of transmission computer and calibration errors. There was a chance to hide the calibration MIL light with the help of HP Tuners, however that exposed more of the actual tuning issues. The remaining check engine light issues were diagnosed down to the voltage rheostats within the accelerator pedal. It was determined that the voltage percentage sent to the ECM to command the throttle body was not what the computer was expecting. The voltage symptoms led to more research to determine if the pedal was faulty or something else was causing the problem. Come to find out there were actually two throttle pedals that were released for my year engine. After further research and some corroboration from my local GM parts counter it was determined the pedal I had in the Jeep was not the correct pedal for the engine and ECM. The correct pedal was ordered and I picked it up the next day. After I installed the pedal I performed a procedure within HP Tuners to reset all the pedal metrics. The pedal response was immediately noticed. The Jeep sounded completely different. I took the Jeep out for a drive keeping close to the house in case something decided to go wrong. The Jeep felt completely different on the road. The shift patterns were more in concert with engine RPMs and torque applied. The fuel rail consumption was well below what it had been. The pedal percentage PID was reading a much lower percentage voltage, however the Jeep had plenty of power. Hard acceleration was more predictable, while gear selection was spot on, whereas before it would take several seconds for the Jeep to “seek” the correct gear. I ventured out a little farther all while noticing how easy the Jeep was getting up to speed and how quiet it was in the cabin because the Jeep wasn’t laboring with bad information. I was able to perform a couple of coast down tests to make sure the transmission would pick up the new pedal percentage values and cause the transmission to downshift as expected. Shifts up and down were much more smooth than previous days. In short, it seems like I chose poorly when I first sourced my throttle pedal for the build. Make sure if you are swapping an LS or LT you have the correct pedal for your engine and ECM!