1999 dodge ram 1500 wont run and keeps setting p1391 already replaced flex plate-crank and cam sensors

So is there a question?

Tune up, coils and wires.

Ladies and gentlemen I have a 2002 ram 1500. 5.9 magnum V8. If you've already replaced your sensors as in cam aka pickup coil located in distributor and crank stop there. Reason why is 1 question. Did you replace your transmission. If yes let's talk about the flex plate. If it has the slightest bend then that's the problem. Some aftermarket crank sensors can be too long. You tighten it down and couldn't tell. I've dumped thousands into mine. Low compression cracked heads. I bought new heads timing gears and chain distributor spark plugs wires lifters and rods. So all that for a 20$ flexplate. As soon as I replaced it started the truck instant fix. No rough idle smooth as can be.

You probably have a bad ignition coil. Which engine is in this truck? 3.7, 4.7, 5.7 or hemi

check engine light and code P1391 crank or cam position sensor

The above can cause rough idle on the Dodge Ram 1500 5.2L V8 Engine.

Can try to replace the sensor, but verify that the wires are ok first.

most likely its the throttle body sludged up . clean the throttle body and butterfly . this will only help if there is an idling problem . ck for codes and ck freeze frame data for more help

Code P1391 Loss of crank or cam sensors,P0340 No cam signal at the pcm. I would replace the crank sensor first. Your cam sensor is part of the dist. on 5.2/5.9 engines.
Hope that helps.

P1391 - Intermittent loss of CMP or CKP.

Generally, this code will indicate that the crankshaft sensor is faulty. The sensor is mounted in a fixed position in the engine block. The tip of the sensor protrudes into the crankcase at a distance of 0.05 plus or minus 0.02 inch from the crankshaft. I would check the wiring harness for loose connections. Inspect the trigger wheel behind the crankshaft pulley and the sensor for damage. replace if needed.


If a crank or cam sensor fails, the engine will not start. both of these sensor circuits can be checked with a voltmeter or lab scope.If the sensors are receiving the correct amount of voltage and have good low-resistance ground circuits, their output should be a pulsing digital signal or voltmeter reading while the engine is cranking.

If any of these conditions do not exist, the circuit needs to be repaired or the sensor needs to be replaced. The location of the Cam shaft sensor will be mounted on the distributor. Use the sensors terminals for testing. Over 7 volts is ok, but anything below that at the sensor will indicate that the sensor wires are bad. If the voltage is low at the PCM, the PCM is suspect.

could be thottle postion sensor

there is also a crank sensor that can keep it from sparking. are you getting voltage to the coil