replaced blower motor resistor. didn't reattach air intake hose to manifold. Started truck and let it run for a while. Started driving. got about a half a mile it backfired a couple of times and cut off. Will not start back.
I have fuel at the rail and spark at the plugs and coil. Replaced distributor cap and rotor. I'm not a mechanic just a old man trying to get to work so I really have no idea what I'm doing Any help would be greatly appreciatted.

 

Welcome to the forum

Do 50/50 test
Spray fuel into the engine, gasoline or Quick Start(ether)
Try to start engine
If its starts and runs then dies you have a fuel delivery issue
If it doesn't start then you have a spark issue
50/50 instant results

You can't test for fuel, and spark testing is not reliable, or tell you if timing is correct
50/50 test is still best test, used since 1880's and the first gasoline engines, lol

And changing the blower motor resistor wouldn't cause this, so its unrelated, not something you did, just a coincidence

 

Thanks for your quick response. I spray starter fluid and got nothing. So where do I go from here?

 

Then its a no spark issue

You should have a CEL(check engine light) on the dash in 1994
It should come on with key on, that means computer(PCM) has power and has booted up
CEL should go OFF as soon as engine is cranking/spinning, doesn't need to start just spin, that means PCM is getting a good timing signal from distributor/TFI
If CEL stays on then no timing/spark signal

If CEL stays on, then just to take it off the table, pull up distributor cap and look at the rotors position, crank the engine, rotor should have changed position, there is a drive gear that can loose its connection so distributor does turn any more

If CEL goes off when cranking then PCM is getting a timing/spark pulse from TFI
Check coil wires, unplug and plug back in to clean contacts

1994 3.0l uses a TFI spark system, but remote mounted on the Rad support probably below the battery on drivers side front of engine bay

There should be a 3 or 4 wire connector on the side of the distributor, unplug it, and plug it back in, this cleans the connections

There is no fuse just for the spark system, pretty much all engine and computer systems are powered by fuse 4, 30amp in engine bay fuse box
Also in engine fuse box, Fuse 1, 60amp, powers ignition switch

 

Thanks Ron,
Going to go try your instructions this morning.
the CEL does go off when it starts cranking so hopefully cleaning the connections will do the trick. That would be an amazing Christmas present. It's been down for a couple of weeks. Depending on the wife for a ride to work is not one of my favorite things.
Even if she is a good sport about it. So far anyway.

 

So distributor is spinning and TFI module is passing the timing pulse on to PCM, that's good

Unhook either battery cable while you unplug and plug back in the wires on distributor and coil, makes sure it's longer than 5 min
Then hook battery cable back up, this will have reset the computer, so it reboots factory software

Do you have a Tachometer?
If so does it move when cranking engine over