What has happened: it started running VERY bad! Cutting out, sounding like it was out of time, wouldn't stay running. My dad drove it like that for 3 days. I watched him trying to back out of the drive way, he'd crank on it till it started, give it full throttle, shift in to reverse and it's stall. He repeated that about 6 times just to back out of the driveway. He said it was stalling out all over town. I tried to fix it so I replaced the cam position sensor, dist cap and rotor and plugs and crank position sensor. It got worse. Now I can't even get it to start at all. I checked fuel pressure, great, 45psi. Checked spark using a in line tester from harbour freight. No spark. Put it on the coil and it had a slow weak pulse. I didn't really trust the tester so I used a new spark plugs to test 2 more plug wires, no spark at all, in the dark mind you. I put in a new coil and the tester looked brighter at the coil, but still no spark at the plugs. I got an old coil wire from the last time I changed the wires and hooked that up, still the same.
I probably should test my new sensors to make sure they are working.
What else should I look at?
It never threw a code.
​​​​​​​Also when it was running my dad said the rpms were slamming around very irradic. He said on the freeway the engine would suddenly slam down to 1000 rpm. Not just like if you let off the throttle, but very rapid.

 

Still sounds like a bad crank position sensor. These trucks really don't care for the aftermarket fellers, try a genuine mopar sensor.

 

I read that elsewhere also. I'll go get one at the dealership tomorrow.

 

Since you started a new thread on the same thing, this thread is now closed.