Why does my Ford Ranger engine died going down the road

Could also be that one or more spark plugs isn't firing dependably. Another possibility is a mostly clogged fuel filter that supplies just enough fuel for the engine at idle not under load but not otherwise. A quick and dirty check for this is to let the engine warm up and then gradually raise the RPMs to about 4000. If it doesn't sputter by then the filter is passing enough fuel for most driving conditions. This would also indicate that the injectors are opertatng reasonably well too. A CHEAP mechanics stethoscope will let you know if the injectors are all operating approximately THE SAME. There should be a steady rate of sharp clicks when any injector is cycling properly-if one clicks but skips that's a problem/ If one sound noticibly quieter than the others that's a problem too.