OBDII Scanner Codes?

Well My XJ decided to start running rough on me today (97, 4.0) Then all of the sudden she dies on me and throws a check engine light. Well I go and get the code checked out and it is a P1398. The guy at AutoZone looks it up and says well that's not right... The scanner is reading a ingnition problem or a misfire. The computer said somthing about low voltage to sensor B or something like that. ANyone got any idea what the problem could be??????



Thanks,
Ray

My DTC code reader says 'No crank sensor learn'....sounds like CPS and typical symptom too, rough and dies. Try unplugging the CPS connector at the back of the fuel rail, clean it out and plug it back in. That MAY work, once or twice. The sensor is at the top of the bellhousing at the 11O'clock position when sitting in the drivers seat, 1 O'clock position when looking at it from the front of the engine to the rear.

Thing is that she was running fine, then sat for about three weeks (for at least 2 of those weeks someone left my CB on and drained the batt down while I was in class in TX) and after I got it running again it was fine. Then one the way home she throws the code and dies. I start it back up and everything is running great but I still have the code???? What gives? I will check the CPS and see if that is dirty but I doubt it. Like I said she has been fine since '98 (had a TPS go out on me) and nothing like this has happened. Just very confusing....

Ray