Sputtering on start & died on highway

I have a 1998 Ford Explorer. It was running fine until last Mon. On my 3rd start of the day , it wouldn’t stay started long enough to get into gear; sometimes it sputtered violently. I tried starting over the next 2 days with the same outcome so I towed it to mechanic. They replaced spark plugs, wires & started (because it was throw lower voltage than normal). It ran fine the short distance home. The next day, it started fine but sputtered in corners/lower speeds. About 12 miles into the drive, which was at ~60 mph, my auto died and wouldn’t start again. Any thoughts what’s going on? Could it be the fuel pump?

Not sure what you mean by (because it was throw lower voltage than normal), but you could have a clogged fuel filter or failing fuel pump. Try replacing the fuel filter and air filter, both low cost. What maintenance history does it have? How many miles, is the check engine light on?