Need help / idea - no power and erratic idling

[toddtheodd]

1992 Chevy 2500 5.7 TBI

Already replaced:
all vacuum lines
throttle body gasket (was looking for a vacuum leak, and found one)
fuel filter
ESC
MAP Sensor

Thought maybe the cat was clogged up... cut it off.

Unhooked the EGR solenoid from throttle body, and blocked off that port on the throttle body. Finger checked EGR, and it is opening and closing easily.

Mechanic hooked up a fuel pressure gauge, and it ready 10psi.

When I start the truck, it dies. RPMs jump to 1200, and right back down to dead. If I sit there and blip the throttle... forever... it'll run. As soon as I stop, it dies.

If I keep on it, I can get it into gear, and get it moving (5 speed manual / L-1-2-3-OD). In 1st, it surges pretty bad until I get it moving, and then it has no power. At WOT, it falls on it's face, and sounds horrible. Like the freaking thing isn't advancing. I can't even check the timing with all the stuff hooked up, because I can't keep it running long enough to get under the hood. I'm stuck in the cab blipping the throttle.
It sputters and coughs something fierce at all throttle positions.

If I push in the clutch and let it idle for a second, it dies.

If I take off the MAP sensor, and advance the timing by hand to about 6-8 btdc, truck will "sorta" run, and while still bogging down at WOT, will at least pull strong at part throttle. This is a brand new MAP sensor.

Oh... and quick note... when I put a jumper in A and B of the OBDI plug to get the flashing lights to read the code... no service engine soon light. The shift light comes on and stays on solid.

I'm about to go check the ground wires now.

What the bloody hell else could it be?

The only thing I can think of is the distributor... It was running fine, and then started bogging down real bad on the highway. Like the cat was clogged.
In OD, it wouldn't pull up a hill, and lost speed bad. In 3rd, I could get it to pull at part throttle back up to speed, and then back to OD.
If I went down to 3rd, or even 2nd, and floored it, the RPMs stopped at 3500, and that was it. Nothing more.

Also... if I put it in L, and really give it the beans, it won't even bark the tires. No freaking power.

HELP!

I need this freaking thing running because it is my daily driver. Right now I'm driving my gf's Ferd Taurus... and I can't do that forever. I need my truck. NEED...