If a low tire made it pull that much, it would probably be flappin'...
Sudden onset suggests ball joint failure, pitman arm or idler arm failure.
All are death-knells for your truck if you drive it...so Don't.
I have ZQ8 box, poly bushings @ A arms, and new Moog Problem Solver idler arm and pitman arm. Steering was still a bit vague until the steering shaft replaced w/ Flaming River shaft and NO rag joint...it's definitely NOT needed. WHAT a difference that made...it's now tighter that a rack & pinion.
Set the steering gear-box so that you can feel the 'tight spot' when you crank on the tire to turn the steering lock to lock.
HTH, Worked for me!
David