Yesterday was delivering an RV west of Chicago. Thankfully I made it though town before the trouble started.

Started running rough; shaking bad, no response to pedal, rpms up to 3500 before shifting, couldn't get to high gear, no power.

I made my delivery

This has happened before and I have been able to run through the gears a few times and the problem "clears" itself. (It will run high rpms then shift hard through the gears and then it runs fine again)

I made it home but now it won't start at all.

We have checked transmission fluid, oil pressure sensor, fuel pump. Have had glow plug harnesses replaced, glow plugs tested, module good. NOTHING, It cracks and cranks but won't start.

I need my truck for work and would appreciate any help I can get, as soon as t can be rendered.

 

Sounds like you ficm bit the dust check to make sure you have 48volts while cranking.

 

FICM was our first thought too. Everything has tested "ok"; FICM, IPR, HPOP, etc. All tests are as should be, tracing wires now to see if the problem is there.
I appreciate the input . . . anything else. Keep the thoughts coming, there may be something we haven't thought to look at.