95 suburban k1500 after about 1 mile of driving loses all power, giving it gas does nothing, oil pressure drops to 0, then truck dies.

Truck has new oil pump, new oil sending
unit, new exhaust from after cat to tail pipe,
new oil coiling lines to and from radiator.  
After these repairs we drove it 300 mile
round trip on vacation and oil only ever
dropped to 20-25 at lowest and we t back to
40 when cool.  I have been given the
possible diagnosis of ECM  , which I was
told could be not sending the correct
signals and that will kill the motor, or
possibly a clogged cat converter.  When the
oil pressure drops the motor stops
responding to the throttle, makes no
strange noises, I know what the tapping
sound is and I know the clanking sound to
be listening for and it makes no
sound....only dies.  Wait 5 minutes or so and
it will start again and drive approximately 1
mile or maybe 2 and it happens again.  I've
put too much h money into this beast to just
let it go, we gotta get her fixed.