My '95 E-350 powerstroke has a mysterious problem.
It shows kilometers not miles, just for information.

I write down the mileage every time i refuel, just to keep track of the average consumption, and it will show me if something is about to happen, like the injectors being worn out.

So, I refueled at 399284 km. and looking forward to seeing it pass 400000 km. in the near future.

Then, on the highway i glanced down and it shows 399999, just in time I thought. Next thing that happened was it changed to 300000

Now I have 301058 km. and counting.

What is going on, this is a digital counter, not a mechanical one that can get stuck?

 

Answers recieved in 94.5 - 97 Powerstroke section.