1996 RAM 1500 5.9 GAS Crank, no start

Truck ran great, parked it and came back the next morning and would not
start. Over a week or two I replaced Coil, Distributor, Rotor, Crankshaft position
sensor, Camshaft sensor (pickup plate), coil wires, injectors, throttle bodies,
fuses, ignition, even tried another computer. New battery, new alternator as
well. I've forgotten what else. Coolant temp sensor, air intake sensor. Anyway
the truck just turns over, and over, and over. One time, it did sputter a little bit
and run for about 1 minute very rough, very low compression it seemed. My
truck is a 5.9 1996 RAM 1500 4x4, and the straightpipe exhaust is black like
sout. It does burn a little oil recently, as i drive it fast everywhere I go and hard.
When I let off the gas she decelerates herself oddly fast I've noticed before.
Never has white smoke when warm, never leaks anything but coolant. Are my
valve seals bad, or piston rings? Do not have access to compression testing
tool. Please help. Does get spark, does get fuel.