I have a 1997 f250 with a 7.3 powerstroke that is hard to start up on cold mornings. I just replaced the batteries thinking they might be the problem because they were the originals. The engine turns over faster now but is still hard to start. Any suggestions? I was thinking maybe the glow plugs...

 

I've got a 7.3l too. same problem. had to change out the glow plug relay on top of engine. very easy to do. It's right behind the HPOP. Cured my glow plug/starting system problem. Do you plug in your block heater at night, Had to find mine, heater is located at the oil filter housing, just follow the electrical line from it to front right of engine and there is a three prong for the electrical. I live central Pa.