4.3 94 chevy cranks sometime most time it wont change plugs , wire, dist,rotor button,crank module...getting good fire .. and fuel but still wont crank

See diagram

no,the pump wouldn't do that. Pull the dist cap and crank the engine,make sure the rotor spins,may have sheared the pin one the shaft.

I have 94 s 10..4.3 v6. it does the same thing have replaced fuel pump and filter,ignition module,cap rotor plugs wires,coil,ground strap...driving down the road jus dies like the key got shut off....for a while when troubleshooting through the parts you could get it to restart.....now when it dies it cranks really hard when trying to restart..ive checked the timeing its fine....if i wait a few min it will usually start...sometimes it will show a check engine light sometimes not......never know when it will happen sometimes jus down the the road from the house sometimes 100miles down the road......sometimes three times in a mile sometimes not for weeks at a time..Wtf...Im ready to shoot it like a lame horse....its a shame too its a sharp lil truck thats a two owner and never spent a night outside in its life...i knew the original owner ...i bought it with 90,000 on it it only has 148,000 now and still looks like new...

Can you take the valve cover off and turn the crank until the number one valve closes, then check the rotor on the dist ?
TDC for number one cyl is when that intake valve closes.
I assume you checked the compression and all 6 cylinders are ok ?
If you have compression and the valve timing is close, you should be able to turn the dist and get it to backfire or something if the ignition timing is the only problem.

coil bad? check the ohm rating to see

you said you repl dist cap that means you don't have a crank sensor you have electronic ing module. remove your elec ing module have it tested most auto parts stores could test your module, or check your coil at the neg terminal. should have power. if not you lost your primary volt from your batt.your secondary power is coming from your electronic ing module from the module to the pos terminal on the coil, when the eng cranks,from the coil to the dist cap , from the dist cap center to the rotor then out to the plugs,this all happen pervided the timing belt or timing chain is ok. the cumbustion chainber needs 3 things , thats fuel, air, and spark.

Do you have spark??? if so, check fuel pressure, these trucks must have 60 psi to run, 50 psi will not work,.

crank shaft position sensor is most likely cause. Do check ignition and fuel pump relays with an ohmmeter to make sure they are not faulty. Check power to ignition module. You can also check crank sensor with the ohmmeter. Check all vacuum hose and also check throttle position sensor.

There may be no injector pulse if the computor does not see a RPM signal.
There will be no spark if the ignition module does not see a dist pulse from the dist pickup.......a RPM signal.
Because you do not have both ......I would suggest to check/change the dist pick up.
Follow the wires from the ignition module inside the dist to the pickup which is also inside the dist.
If it is just a bad dist pickup....keep all your old parts as good spares.
Also...is the dist turning? to provide a RPM signal?
You will have to remove the dist to change the pick-up.....mark your timing locations......"rotor position" and "dist body location"before removal.
A quick test before installing the "repaired dist" .....plug it in the the truck wiring and turn on the key....DO NOT CRANK THE ENGINE OR YOU WILL LOSE YOUR DIST ROTOR CORRECT POSITION......as you spin the dist by hand .....the injectors should spray.

Reaching your Findings I would go to Checking the The Idea of Timing chain Problem
#1 Top Dead Center on Compression stroke, remove dist cap and see where Rotor is Pointing, it should be pointing at #1 Plug wire if not Timing chain & Gear Replacement time. If all Is Well there PLEASE Confide in Me I would Love to Help Thats My Mission here
Good Night and Take life EASY, Rejakwilson