Ok, similar problem, different engine, we had similar symptoms leading up to shut down, it went into limp mode (10mph) intermittently, until it finally would not start. I borrowed an OBD reader, which showed fuel codes and crank sensor code (intermittently)
It was diesel sludge in my 6.5 chevy diesel, clogged up the filter, 3/4 inch of sludge in the bottom of the tank, sender unit was completely clogged, so the fuel system was not getting enough fuel.
Cleaned filter housing, replaced filter, blew fuel lines through, changed lift pump (I don't think I needed to do this), took sender unit out of tank, cleaned completely, drained tank, through the sender unit hole, scrapped as much of the sludge out with paint scraper, then used thinners to break up the rest and wipe out with tissue.
Put it all back together, hey presto, all fixed, she even accelerates uphill not
Hope this helps someone.
2002 Georgie Boy Landau
6.5 TD Chevy V8