[Boog]

You can probably give it just a little bit of throttle and it turns just fine right? I have 2 trucks that do this sometimes.
It could be the pump. Or it could be the steering sensor.
Just to eliminate any parts of the steering linkage being the cause. Jack the front up and place on jack stands. With the engine off turn the steering wheel from lock to lock and feel for any hard spots. Also do a visual of all the front end parts noting wear items like tierod ends and pitman arm, ball joints, etc. Grab the tire and try wiggling side to side and up and down to insure everything is normal there.