97 GMC diesel just quit while driving on highway

Have to service these a lot it's the MAP sensor ( manifold absolute pressure sensor ) this should fixya.

sounds like your timing belt broke

TRY CHECKING THE THROTTLE POSITION SENSOR, OR A LOOSE GROUND WIRE IN ENGINE COMPARTMENT NEAR THE ECM.

check fuel pressur, filter and fuel pump...sounds like it isnt getting fuel

sounds like the fuel driver module is on it's way out
mounted on side of fuel pump square box black in colour held on with 4 screws
and silicone style gasket
i havs replace quit a few over the years runing a fleef of small bus with 6.5 diesel engine

there is water in the fuel, there should be a fuel water seperator in the engine compartment, look in your owners manual and it should tell you the steps to drain the water from it, it should take a few minutes

Sounds like a compression leak from one or more injectors into the fuel system. I am guessing that you already changed both the frame and under hood fuel filters in the last 15,000 miles? Be sure the cap on the frame fuel filter is tight, any gap between the cap and housing can cause fuel to return to the tank instead of going filtered o the engine.

it is big end bearing.

Safari's tend to have problems with the rotor button on the distributer. Your's may be going bad. At first the van will stall as you described, due to a jarring of the motor, ie: a bump. etc., and then it will restart.

After a while the rotor button will fail completely.

I have had this same problem with two safar's and this is the solution that I have found.

If the pump is not rotating all the time then it's due for replacement. They are not supposed to stop while engine is running. 227K miles is a lot of miles for any engine component.