I have a 7.3 that loses power then comes back. The cycle is running good for about 20 miles and then it fades to where I can only go about 40mph. Then in another 15 minutes it comes back to normal. Any ideas. Someone did mention a sensor at the front of the engine that may cause this. Any ideas.

 

wrong area bud. your in the IDI section. post this up in the powerstroke area. might help ya there.