I have a 2000 F-450 with the 7.3 diesel, and it seems to be taking too long to start (cranking too long before the engine fires). Other than that, it runs and pulls great, has good power and does everything as it should. The glow-plug light seems to be on for the "normal" amount of time, so I don't think the glow pugs are short-cycling as with a bad relay. Anyone have good ideas? Thanks!

Did you try testing your glow plugs to see if they are still good ? Also, have you emptied water seperator and checked your oil level?

Try using full-synthetic HDEO.