2004 f350 gutless
Ok so I was driving my grandfathers 2004 6.0l today and I was pulling a 2 horse trailer nothing of significant weight and while going up a very steep grade that's probably 15 miles about half way up it completely lost all power I had it floored and it was crawling along up the hill at 40mph and 2000rpm. This isn't the first time it has done this and after you finally top the hill and get onto flat ground you can step on it and it takes off like a bat of hell. The truck is all stock other then an egr cooler. Does anyone know what could be happening?