This is kind of long so bear with me:
Well, when I got to Stone Mt. GA campground last week and got set up and was driving around with just the truck, I noticed what seemed to be a shudder when accelerating around 45-50 mph with the OD on. The next few days the shudder kept getting worse and I started to faintly notice it with the OD off. Well, I hooked up and headed back to NC. Got back on Sun. night and went out Mon. to run some errands and the shudder was BAD at 45-50 with the OD on. I was thinking "great, the transmission is toast" being that I purchased the F150 used and don't know how it was treated by the previous owner. After much research I did narrow it down to the transmission OR a cylinder misfire. So I went out and got it to shudder and FLOORED IT. The truck launched like a scaled dog but I could tell it wasn't right, like it was missing. This FINALLY caused the check engine light to flash. After stopping at the end of the road the truck smoothed out and the check engine light went off. I got my code reader out and it threw a cylinder one misfire code. I changed the coil for that plug and so far it has fixed the problem. I need to change the plugs, but that is a entirely different story........