'92 16v sidekick

[danstrayer2]

big problem, please help if you can.     Last night I backed up on gravel road for 300 feet, at high speed, pulled in and parked. This morning this happened:
   Good start, all sounded well and normal as it has been for a year:  in less than 2 minutes, extremely rough, only run (barely) at certain throttle openings, eventually dies completely, heavy fuel usage. No restart.  Let sit for 20 minutes, good start, in 45 seconds goes to extremely rough, then no run. Will run at high RPM, with some occasional misfire.
   Here is what has been done:   
 removed cat from exhaust system.  Same.
    Fuel volume from rail= very good. Fuel pressure in rail just under 40 psi. Return fuel line OK. Tank pressure relieved.
    Rail leak-down test=OK, holds 35 lbs for 10 minutes, (very slight drip at my fittings).
    Air cleaner removed.
 here's the killer: Vacuum test about 10-12 inches hg.   Plugs very sooty.  It's lke fuel is justbeing dumped, but injectors don't leak, even if one did, all plugs are sooty. 4 injectors did not fail at one moment.
 I saw the FSM on exhaust blockage, removed exhaust manifold completely . Problem/symptoms remain.
Could this be valve timing as in slipped belt?
MAF is fine. EGR is OK.  It started when I backed up, WOT...coincidence?
   I am  stumped.  It runs really well just like always....then 1-2 minutes just deteriorates to will not run. What can it be?

are you going to run the engine 300,000 miles on a 60k mile cam timing belt.? sorry had to ask... common failure this. and worse next.
is the front crank pulley 17mm headed bolt loose?  94ft/lbs only is spec.

compression is 180PSI not 80.  do a compression test on any engine, that will not run or has low power. first ( do it with the throttle blocked open)
at sea level not DENVER.

KEY ON< CEL lamp must glow does it.
and then with the DLC diagnostic jumper inserted (paperclip) DTC code 12 blinks out, (means good)  all others bad, or worse.  
worse CEL dead.
worse CEL can not blink but stuck on.  (turn off CEL nag switch if car is FED and not Calif, marked on hood sticKer)


see my sneak a peak/

https://fixkick.com/t-belt/sneak-a-peek.html

or just do compression test on front #1 , a 15 min job, that 1 plug out, block throttle open if 80PSI not 180, do them all if #1 fails.  easy logic that.

I do not think going backwards is it, but if it cause wiring to break loose , engine harness or connectors sure.

The ECU can go to failsafe (limphome mode) or worse BACKUPMODE.
all those suck fuel like mad and wants to flood the engine
use the DLC get the ECU flashing codes,  do that first , if the CEL lamp is dead  that is a bad lamp or stuck in HORRID BACKUPMODE(means bad ecu)

a bad ECU is most times just needs new CAPS.  (they love to fail on this car if black caps and marked RUBICON)

compression steps and expected results are correct.
https://fixkick.com/compressiontest.html