Jerky bounce over bumps, 2005 F350 diesel

Thanks for the replies!! Now I know the official term for this. My ball type 5th wheel is frame mounted under my flat bed. Open the hatch and flip the ball up so no way to change that. I also use this truck for my farm hauling the livestock trailer. My next truck will have the regular 5th wheel setup with the airride hitch. Few years away when we can travel more. Tied to the farm right now until my daughter gets out of college and can run things. As one commenter said I have already been down the egr/oil cooler and injector route. Thankfully I have the Good Sam extended warranty, They hate me I am sure. But I bought and had the truck custom built for me new so I know it inside and out. Plan on running it until it won't go anymore.

Again Thanks for the tips!!