trouble shooting becomes difficult when the wrong fault codes are used.
Ok, the P0320 indeed is a fault code for the crank sensor circuit. That the problem starts after heating up the engine also points towards the crank sensor. It most probably is the sensor itself, however i would check the wiring as far as possible from the sensor to the PCM. The crank sensor sits just above the starter motor, which is mounted to the transmission bell housing on the right hand side (as seen from drivers position). You will have to remove the starter motor to get access to the crank sensor. If you are going to change the sensor, then you best go with Mopar, since parallel sensors are known to give problems.