Ok, I'm feeling stupid. I bled brakes many times on different vehicles and this is killing me.
93, 4wd, 4 wheel disk brakes.
My master cylinder was slightly leaking so I replaced it. No big deal.
Bench bled the new one, bolted it on, bled the brakes, the peddle goes to the floor. Did this several times. started with the load sensor, followed the recommended pattern. I even took the negative battery cable off.
At this point, thinking it was the MC, I bought a new one. Same thing. I can get the peddle pumped up with the engine off, but once I start it, right to the floor.
Feeling pretty dump, Terry