So a little update. Over the past couple weeks, whilst I had little time for diagnostics, the driving conditions described at the beginning of this thread have worsened. Though the behavior continues to be intermittent in nature, it became more prevalent in the lower gears, including very rarely in first gear. When this would happened the Jeep went from annoying to darn near undrivable. In addition, despite the frequent misfires, backfires, and engine shuddering, the truck continued to operate without the illumination of the MIL
So last Sunday, bending to your popular opinion , and seeing the logic in it, I replaced the TPS. This worked great for about 3 miles, then right back to where I started, still with no MIL code to give me further diagnostic direction. I was happy, and then sad, and during the intervening week, it has worked great for the first 3 or so miles, and then kaabam, misfire, backfire, jumpy engine operations...So I reset the PCMs adaptive memory, with little effect, and then yesterday tried to use a scan tool to see if thre were perhaps some codes that stored but hadn't tripped the MIL. Unfortunately when we plugged in my buddy's scanner into the data connector, there was no power.
So I started today thinking I would be spending my day chasing wires for the datalink connector. Fortunately when I tested it, it had good power and ground continuity. Still there is no MIL when we all believe there should have been, at least once, and yes the MIL does come on at start and then go off, just as prescribed in the manual. As such, I decided to do a little experiment, and disconnected my bank 1 sensor 2 O2 sensor. For the first few miles, the Jeep drove better, but the same as it has been, still without illumination of the MIL.
Suddenly after about 7-8 miles, the truck shuddered, and on comes the MIL. Now I was fairly certain this fault was due to the disconnected O2 sensor, I still pulled into Autozone to be sure. Sure enough, the only stored code was for an O2 sensor fault. I left the sensor unplugged and continued my errands, a distance of about 15-20 miles..
The truck is running like a champ, albeit with the MIL lit up. So I glad as I am that it seems to be fixed, I dont understand. Can anybody think of a reason why disconnecting an o2 sensor should correct the erraticness that has been driving any distance of late. I can not seem to come up with any. Thanks again for any thoughts ya'll might have....