Power steering

Cars always steer easier when they are moving, so this suggests you have a weak power steering pump. The clue is the power assist will come back when you raise engine speed a little. Also, a weak pump results in loss of power assist in both directions at the same time.

Internal leakage in the rack and pinion steering gear can cause loss of power assist too, but usually you will have lack of assist in just one direction, and that will come back when the engine warms up. Each day it will take longer before the power assist returns, and after a few weeks or months you will lose power assist in the other direction too.

Make sure tires are inflated properly