96 s-10 with a 4.3 vortec 2 wheel drive. With truck running down road all of a sudden engine cuts out and shuts off, no power. Turn off ignition and turn it back on, engine starts and runs for a mile or so, shuts off again. Repeat, turn off and turn on. This can happen all day long. Not sure if ignition is shutting off or fuel.

 

Try changing out your fuel pump relay with the horn relay and confirm its functionality. Its possble that a bad relay can be causing your problem. Otherwise test the ffunctionality of the ignition spark.

 

Had same issue... stopped completely one day. Towed home no codes, after a month of tinkering with no start, I found a hidden break in the coil wiring... the plastic was not broken but the wire under it was... I would experience occasional engine shutter while driving. When cold it ran but when wire warmed up it would lose the connection and truck would die. Soldered wire back together and she fired right up and still runs great years later.

 

There is always the shotgun approach, replace everything, and hope , first, you installed good "new" parts and just maybe you might get lucky.
Of course there is the other approach, check for fuel and spark then go from there to determine why one or the other OR both are missing.
A good idea would be to check if the system has any codes to provide some guidance.
Depending on what is found will determine what you need to do next.

 

yeah..a failing fuel pump or even a dirty fuel sock on the fuel pump can also cause this issue