GMC Repair: When brakes applied truck dies, petcock, fuel filter

Question
We have a 1994 6.5 diesel.  200,000 miles. When the brakes are applied it dies.  It will start a few times after it dies, then it will start just turning over but not starting.  It is only driven short distances under 10 miles.  Will start the next morning, so far.  Engine is getting fuel.  Fuel filter has been changed.  What could it be?

Answer
Hi
Could you please tell me if any codes are stored?
If so what are they?
Engine is getting fuel where? At the petcock on top of engine or at each injector nozzle?
should be 4psi at the petcock (cheating).
Any smoke? If so what color, black, white or gray?
does it run OK otherwise?
Please follow back
Pawl