Pulled this code out. Truck runs fine, no misfire or erratic idle. I do get poor gas mileage about 9/10 mpg. Should I be worried that a sensor might go bad?

 

i would reset the pcm. (remove neg battery, turn on headlights for 30 seconds). then monitor it to see if it comes back. if it comes back regularly, then do something about it.

Is (was) the CEL on. and if so for how long? and did it go off on its on?

P1391 - Intermittent loss of CMP or CKP. cmp is cam position sensor, under dist cap. ckp is crank position sensor, passenger side bell housing. both are pretty hard to get to. also be aware, some members report problems with non-mopar crank position sensor. no good reason why, but they do.