Curtis Whitehill

This one does it at any RPM if you slowly bring it up, just steadily give it more and more throttle. But if you hammer on it, it stumbles, skips, throws some white smoke then clears up and runs the way its supposed to. Going down the road is its fine if you are hard on the throttle, but again if your little with the throttle just maintaining speed or trying to speed up just a few miles an hour it smokes and skips. My other thought was Rack Position Sensor or the Pump itself. Either way the pump has to be sent to a pump shop. However I would like to test the Rack Position Sensor before I just tear the pump off and send it out to get rebuilt. Does anyone know the pin out proceedure or way to test the Rack Sensor and the Rack Sensor Wiring from the V-MAC Module. The truck has the V-MAC 1 electronics and Bosch Module.

Changed Timing Sensor on pump, had no effect on runability. Any other suggestions?

1994 CH613 with an E7 400 that studders and smokes at idle until warm. After temp reaches 180 degrees truck quits studdering and smoking at idle, but between 1300-1600 rpms it has a bad studder and smokes horrible. It is not really down on power, it is not using coolant, not using oil, very little blow by. Truck has 365,000 miles on it. Checked for a shorted Rack Position Sensor, found nothing. Has all new reman injectors. Any thoughts?