1997 Isuzu Hombre • 180,000 miles

Started happening when I put it in neutral while slowing down, the truck would shut off. Twice it has shut off while driving at constant speed. The truck did not lurch, I just happened to notice, while my foot was on the gas pedal, the speedometer was going down. I turned the truck off, and back on, and it was fine. Replaced the fuel lines and filter. Let it run for about 20 minutes, in neutral, and it shut off. Put two bottles of Techron, a fuel system cleaner that we were told is the same as GM uses, and ran it through. Gas tank is full. A few months ago we replaced the ignition, and it was fine. Not sure if the coil needs to be replaced, if this is an ignition problem, or a fuel system problem.
December 14, 2012.

Is it running rough? Have you checked things like vacuum leaks, fuel pressure?