svtsnake03

hi all, well my jeep just turned 120,000 miles and now from what i see a common stalling problem at idle and when coming to a stop. i found some info on the screws on pcm having to be longer. also maybe the crank sensor could be bad. any one have or had any issues like this? any help would be greatly apprecated. also threw the code p0320-
No reference signal (crankshaft position sensor) detected during engine cranking.