I am new to the diesel world and would like to purchase a 2003 ford super duty f-250 xlt 4x4 7.3. It has 220,630 miles on it coming from gas i know this many miles is very bad and can start breaking down but I read about diesel engines that many miles isn't a lot at all. As well as I noticed all used diesel engines are high milage why is that and should I purchase the vehicle or not? Everything looks well kept on it. And is maintence harder on a diesel truck?