Chrysler Repair: 97 Dodge Dakoda 3.9L p1391 Nightmare, dodge dakoda, crankshaft sensor

Question
"My father and I bought this truck, a 1997 Dodge Dakota 3.9 V6, as a repo. Initially my father mistook what we have identified as a p1391 code as other problems, we repaired several other codes leaving us with this one p1391. He has since rebuilt the entire motor, replaced multiple sensors (including the O2 sensors, Crankshaft sensor), the distributor, torque converter, checked the fuel pressure, new Champion plugs, new wires, and others. The original problem still remains, although we have removed several codes we are left with the P1391. The problem is that both sensors were replaced. The truck seems to most affected when it has been sitting for long periods of time. The truck with hop and skip to the point I have to pull off the road. After several agonizing miles, the truck eventually straightens out and rides smooth, except up steep hills where it will hop after it shifts to 2nd. Also at startup the truck idles between 800 and 2.5k if it has sat long enough and it's cold outside. The worse the idle variance, the worse my first few miles will be. Any ideas would be very much appreciated, we are truely running out of things to replace!"

Answer
Hi Christopher,
If the 1391 code persists, comes back after you have erased it by disconnecting the battery briefly, then you have to believe either the cam or the crank sensor is faulty. Unfortunately I don't have wiring diagrams for the 3.9L engine so I can't give the connection colors or pins.
But based upon other front wheel drive V-6 engines of that era, you should find one of the three wires at a sensor has 8V on it. that the black/light blue wire is a ground lead, and that the third lead is the signal lead. If you put a meter across the ground and the signal lead and turn the engine by hand you should see the reading pulse between 5 and 0.3V several times per crank revolution, though at differing rates for the two sensors. Do this testing when the engine is acting up badly. The cam signal wire may be tan/yellow and crank signal wire may be gray/black if the pattern used elsewhere applies.
If the pcm pin assigments apply you should find the sensor ground wire on pin 4, the cam sensor signal wire on 44, and the crank sensor wire on 24. So check those wires for continuity and make sure the signal wires don't have intermittent shorts to ground when you shake the harness. The 8v wire may be orange and connected to pin 7 of the pcm plug.
Use fine straight pins to probe through the insulation of the wires and/or probe around the socket into which the wire fits at the plug proper in order to make contact for these measurements. Keep checking for fresh codes.
The other thing you might want to check is the exhaust gas recirc valve which may have sticky valve stem. If you spray some WD-40 on the stem and work it back and forth you might free up a condition where in it is not closing tightly when at idle  or when accelerating, and that will thin the mixture accessively. The egr is not well self-monitored so that is why I suggest looking at it, even without a code.
Roland