How do I maintain a 7.3 Power Stroke?

Start with records. A clean 7.3 Power Stroke should have regular oil and fuel filter service, documented coolant maintenance, and evidence that common age-related items have been handled. Before buying, check for hard starts, glow plug relay issues, valve cover harness problems, high-pressure oil leaks, fuel bowl leaks, charge-air boot leaks, and excessive blow-by. Look under the truck for oil seepage and rust, then verify that the transmission shifts cleanly under load. For ownership, keep maintenance boring: quality oil, clean filters, coolant checks, batteries and cables in good condition, and no aggressive tuning unless the supporting parts and gauges are there.