Died going down the road like you just turned the key off eveything still works just wont start when i checked the coil for fire I found something very strange the coil was firing all the time with the key in the on pos.

Check fuel pump.

Check the Crank Angel Sensor

Just an Idea. When it dies next time check the relay temperatures, if you can. Once I had a fan relay which would over heat and the radiator fan would not work. After relay cooled down it would work(This usually happened when I was stuck in traffic). Could be a fuel pump relay. If relay is a lot hotter than the other relay could be bad relay. My thought is it will not cost you anything to try it. I think it may be something electrical over heating. 30 years ago my thought would have been the coil, when the coil started going bad it would heat up and the car would die till it cooled off.

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...

Faulty igniters will cause intermittent no starts.

Their is a computer chip behind the antifreeze bottle check the second wire harness play with that while someone turns the key it happend to mine the same thing and started right up

if you are getting no fuel it would more than likely bee the fuelpump

you have pcm problems or ASD relay problems.they both control the fuel and ignition.

i know that if ur car died it most likely has something to do with the alternator or the process in which the fuel gets to the spark

It seems you have a timing problem. Have the engine timed properly. If that does not work it could be a craked rotor or distributor cap. have all these checked.