Odd Error Codes '96 4.0L, Auto

I have a '96 Cherokee Classic, 4.0L, Auto. A few mornings ago, I started it (cold) and it had a bit of a miss but cleared up in less than a minute. This condition continued with every cold start. This afternoon, again, ran with a miss but the check engine light came on. (Miss goes away after a minute)
I got home & did the key on-off thing.
Here's what I got;
12 - Battery disconnected (strange since the battery's been hooked up for months)
43 - Misfire (I knew that)
43 - Misfire (yes, flashed duplicate)
56 - ????? I know that 55 is end of codes, but 56? (I never got a 55)

I ran the test 2 times to make sure I counted correctly. Can anyone give me some insight? Thanks in advance for your help.

After enough of the code 43 errors the cat will be overheated from the extra fuel.You probably have enough miles on the motor that the distributior has enough wear in the bushings to cause too much gap in the pick-up-thus the miss-fire code.
56 code ? The codes repeat twice,maybe it was the start of the 12 code again ?
Wayne

Thanks Wayne, I discovered last night that the #2 sparkplug (Champion Platinum) was fouled (greyish-tan ash) I cleaned it up & the checked engine light went out. I drove to work (so miss upon cold start-up) I did the key on-off again. and got 12, 43, & 55.
Plugs, wires, cap & rotor have less than 5k miles. The Jeep/motor however have 134K.
I guess I have a weak firing plug?

I've got a listing of error codes culled from FSMs on my website - you may want to check it out. It's in the "Tech Archive" section.

The 1996 Model Year was OBD-II, so refer to those codes. As I recall, I have them listed by the two-digit Chrysler number and the SAE "P" number in the listing.