1998 Jeep Wrangler 2.5 liter dtc P1391
1998 Wrangler (2.5L), manual trans, P1391 code.
Checks to be done:
*Check the cam sensor under distributor cap.
* Check the crank sensor on bell housing.
*Check resistance to ECU for both sensors.
*Check for signal at ECU. – Cam sensor should show 5 volts and 0 volts , and get good pulses from the crank sensor.
*Check the distributor shaft for side to side or vertical play.
*Check flywheel for missing teeth.
In our case it was the ignition coil and the distributor shaft had a side to side play.