I have a 2011 F150 XLT 5.0 4wd with about 127,000 miles on it.
Lately I have been having an issue with stiffness when I turn my wheel. This issue doesn't happen all the time but its defiantly noticeable when it does. It's mostly after it sits over night and I get in it for work in the morning. I know it has the electric assisted power stirring and I ran a diagnostic to see is I can pull any codes for a bad sensor and got nothing. I have a leveling kit that raises it up about 2 inches and aftermarket rims 20in and tires 33in with 20mm offset on it (I know this can cause more ware on the truck). I'm thinking I'll probably have to replace the rack and pinion but I'm hoping for a cheaper fix. I do the work myself but just trying to keep part cost down as much as possible. If anyone knows anything that would help please let me know.

*Worst case scenario if I have to replace the rack and pinion is there anything I can do to help prevent this from happening with the wheels I have on now?

 

check the lower steering shaft first, those were not uncommon

 

If it is worse when cold and improves as the truck warms up points to the rack & pinion. Condition is known as "morning sickness".