99SuburbanTX

Wanted to get back to the group with the cause. I finally decided that the fuel pressure regulator I had replaced was bad. I returned it and got a replacement. When I wen to start the engine it rotated and then locked up - like it was flooded.

After essentially giving up on my ability to diagnose the problem with the tools I had available in my garage I finally broke down and had it towed to a shop. The cause was a #5 fuel injector intermittently hanging wide open. This became clear after replacing the fuel filter and installing the 2nd fuel pressure regulator. The combination was finally delivering the correct pressure and volume of fuel making it stick wide open and some "excellent" hydro-locking of the cylinder.