Lastman... a power steering system is designed for a good assistence in low speed and it will become more stiff at high speeds to avoid over steering and thus accident...so ,switch of your Jeep...and open the bonnet once....try to make sure the type of power steering used in your jeep...if its a hydraulic one just check the hydraulic reservoir tank for fluid...if its in within level, check the driving belts for any slipage....check the drive and driven pulleys of the system...check for any leak in hydraulic system... and check any blockage in same rootings....check assisting gear box for proper lubrication...check all gear wheels employed...check the hydraulic out put pressure of the pump...in the case of an electrical system...check the brush set of the motors, and speed controllor....crown and pinions....lubrication....
