Hi Scotty, Howdy from Texas! I have a 2006 Jeep Grand Cherokee 3.7L V6 4WD automatic with 140k miles. I am experiencing some resonance during acceleration at specific speeds which could be related to a CEL that has disappeared on its own.

I went on a road trip a few months ago. Along the way there, we drove the car off the pavement at high speed so were sliding/bouncing everywhere but luckily didn't flip over or hit anything. A few hundred miles later I got P2096/P2098 CEL but felt nothing wrong with the engine (no shaking or loss of power). The CEL went away the next few days, however I had started to notice a resonance sound and slight vibration on steering wheel and gas pedal, when accelerating at speed between 45~60mph. As soon as I let off the gas, it was gone.. During those days, I took the car on some dirt roads and light off-roading. On the way back, the CEL came back and stayed a few days, but still felt nothing wrong with the engine. The CEL has been gone for a month by now, but the resonance/vibration is still there, and now the speed range is expanded to 35~60mph.

I am suspecting the CEL is not due to the cat. I had a misfire that clogged the cat 3 years ago so I replaced the whole cat assembly, pre/post cat oxygen sensors on both sides, cylinder 1/3/5 spark plugs/ignition coils. I have only put on 12k miles since then. There is no scratch marks on the surface of the cat that my near accident could have caused, and when I bang the cat with my hand I do not feel any broken pieces inside. Maybe it is the bad fuel quality in that remote area that caused the lean bias? Could this CEL cause the resonance? I have read similar posts, and suggestions include the suspension system but I recently replaced the front/rear shocks with bilstein 5100s and Moog upper/lower control arms (upper CA made in USA and lower CA made in Taiwan). The tires are brand new too.

Any help is appreciated 😀