UPDATE: CEL came on last week again & took the Jeep back in to the dealership. Code P0306 came up. Leak-down test failed for cylinder #6. There were vibration marks on end cam lobes on cylinder #6. The head was replaced with an AC head, as well as valves, lifters and rocker components. It is quiet now on driver's side. No change to driving characteristics as my Jeep had good mileage and power before. I will be watching gas mileage to see if it remains in normal range, as it is a little low now, but have not driven the Jeep much yet. MAP sensor issue was related, says dealership. Hopefully, they're right.