I fixed my problem yesterday. I,m not sure exactly what the problem was but here is what fixed it. It has only been about 20K since last plug change. I decided to change again and check cop while doing this. I went with motorcraft plugs and used dieelectric grease while re-installing. I noticed the plugs that I took out were white as if to lean or to hot they were bosch platinum. The cop's are bad about not attaching firmly to spark plug cap. I also noticed that one or two spark plugs seemed loose while removing hard to tell exactly because its a b$^*% to get to some of them.I drove to work today pulling my atv on trailer which is when I noticed this problem the worst.Its not doing it anymore also I slightly noticed more power and while coasting down hills I could feel the truck slowing down while coasting down the hill engine compression was stronger. I think it might had been a loose spark plug. I tightned the new ones pretty snug. i COULD A SWORN IT WAS MY TRANSMISSION WELL ATLEAST ITS IN GOOD SHAPE NOW