The Motorcraft ZD-30 glow plugs are exactly what you need for your 7.3 Powerstroke engine from 1994-2003. These are the OEM Ford glow plugs, so you know they'll fit perfectly and work perfectly. They have a lower failure rate than other brands, so you can count on them to last and they do not separate inside the engine, so you don't have to worry about any damage or mess. Plus, they're made with the highest build quality, so you know they're built to last. So if you're looking for a reliable, long-lasting glow plug, the Motorcraft ZD-30 is the way to go.