Recently my tachometer will start to bounce from 0 to actual engine RPM. "Check Engine" light immediatly came on the first time this happened and has not gone out. The engine seems to have a bit less power when this is happening. Later, I shut engine off at drive through window and when I restarted the engine started to surge like I was bouncing my foot on and off of the throttle pedal. I had to shut engine off and restart. This moring my truck barely started after stoping for breakfast.

I had my VP44 rebuilt less then 10K ago, so I hope it is not a pump issue.

Questions:
-Has anyone had a similar experience? If so, what was the problem?
-Will an OBDII scanner pull engine codes? Or do I need to have a dealer or Cummins dealer pull these codes?

 

I don't see any gauges in your signature?

Sounds like the Crankshaft position Sensor, and when it goes south, I believe the truck goes into a lower-power condition ("limp mode").

Autozone read my codes and came up with the CKP, I had the same symptoms, but mine inclued the ammeter showing little / no charge.

 

I agree with Rauschbo, my brothers truck had similar symptoms when his crank position sensor was going out.

 

thats me! when mine went out...all three times...i got a CEL, bouncin tach, then it wouldnt start at all (ecm didnt know where engine was in its rotation, and wouldnt inject fuel) turns out 2 of the 5 bolts in tone ring on the crank were layin in the bottom of my pan. if your sensor looks eaten up you might wanna look into this (puling the pan) if not just replace it and motor on