Cat 3406E no power/ miss while under load

I have a cat 3406E in a T800, it runs fine at idle and bobtail but when you have a trailer on and try to give over half throttle it bucks and jerks like its not running on all cylinders. Shop said it had a code in the computer "DGPS differential - voltage below normal or shorted to low side". Check engine light is intermittent. Sometimes at startup the engine will run rough and spit white smoke until you rev it up then it will clear out. Any help is appreciated, thanks.

 

You need to run a flash code using cruise and maybe we can narrow it down. It could be injector, sensor, transfer pump, regulator valves, fuel filter, just lots to think about. Count flashes will have 1,2,3 flashes then pause and count the next series of flashes. There will be a longer pause after that and starts a new code.

 

Engine serial, year model, and specific code #. We would like to help you, but we need specifics. I'm not familiar with the DPGS differential code, but there are a few gazillion things I'm not familiar with.

 

It's a '97, to my knowledge no blink codes. Fuel filter and separator just got replaced no change in running.

 

I don't know exact code the shop wouldn't tell me. Last 6 of VIN is 733084. I'll go out and get the engine code.

 

Engine # 5EK78680

 

That's engine serial #, follow Maggards advice on blink codes. Key on, engine off, turn cruise on/off to off, and hold cruise- set/resume switch in either position for codes.

 

It's about midnight in east ky, and about 11 in west ky. I don't know how much longer I can keep my eyes pried apart. Does it blink a code?

 

2 blinks, a short pause, then a 3rd blink

 

Another cup of coffee, if that is a flash code 21 blink, then your actual code is a 41-3 or 41-4 , and both are related to your throttle pedal on the 8 volt input/output. Which sounds like you have a dead spot in your throttle pedal potentiometer. That would mimic the problem you're describing. Check your wiring right around the pivot point of your throttle pedal, check your pin connections on the potentiometer, and if nothing is found, change out the potentiometer assy.