The Jeep ran kinda rough after the EM was installed but now it seems to have settled down and is running great. I also replaced the ERG and O2 sensor.. I even noticed an increase in horsepower(not much but noticable). My old exhaust pretty fell out with no hassle so I know it was shot. Not to mention the Jeep sounded like a rice burner. Sounds much better now. But I do notice a sound similar to diesel engine when I'm standing looking over the engine. This is with the engine idling at 900 rpms. This is the sound that concerns me. It's not that loud, could be valves rattling. Didn't notice it before. Either way as long as the sound I'm hearing is not a leak I'm happy.... <img src="/forums/images/graemlins/cheers.gif" alt="" />