When the steering wheel is turned to the right or left, it feels like the steering slips, or lets go for a couple of seconds. This also occurs at highway speed when driving straight It jerks, but not all the time, only occasionally. Sometimes more than others, especially when it's cold.
It has gradually become worse, and we are hoping to fix this ourselves, if we can figure out what it is that needs fixed!
You can feel it especially in the steering wheel when turning to the left. I haven't noticed it when in reverse.

 

Is it 2 or 4x4?

 

Might be the infamous intermediate coupling.

 

4x4. .. What I'd an intermediate coupling?

 

At your dealer's parts dept, gmpartsdirect, or Rock Auto.

 

Does anyone have any actual experience with this issue?

 

Does it feel like it sometimes is really easy to turn at lower speeds?
It could be the sensor for the speed sensitive steering, its located on the steering column. It can be very intermittent and can freak you out at lower speeds...

 

Sorry for the sloppy post I'll try and look for more info on this later today if this sounds like the problem you are having....


Variable Effort Steering Description
The electronic variable orifice (EVO) system increases or decreases the amount of fluid leaving the power steering pump. This provides the driver with a comfortable balance of steering wheel feel and power assist.

At vehicle standstill or at very low speeds, the system allows full hydraulic fluid flow for maximum power assist and reduced steering effort. As the vehicle gains speed, a variable orifice closes at the steering pump which reduces the pump fluid flow. This action provides a stiffer steering wheel response for an improved road feel and a greater directional stability at highway speeds.

A sensor mounted on the steering column detects the steering wheel movements associated with defensive driving maneuvers. A control module uses this sensor input and the vehicle speed in order to adjust the amount of current to the solenoid.

The EVO system consists of the following components:

• The power steering (PS) solenoid actuator is located on the power steering pump discharged fitting.

• The EVO/Passlock™ module is mounted on the instrument panel carrier, beneath the radio.

• The steering handwheel speed sensor (HWSS) is located in the lower bearing of the steering column.

• The vehicle speed sensor is located on the transmission output shaft or on selectable four wheel drive the transfer case output shaft.

• The powertrain control module (PCM) is located in the engine compartment on the left inner wheel well panel (diesel engines only).

• The vehicle control module (VCM) is located in the engine compartment on the left inner wheel well panel (gasoline engines only).




Steering Wheel Surges/Jerks While Turning
Problem
Action

Low power steering fluid.
Add power steering fluid.
Check the system for leaks.

The pump belt is slipping.
Refer to Drive Belt Replacement or Drive Belt Replacement in Engine Mechanical (5.0L, 5.7L, and 7.4L) or Drive Belt Replacement in Engine Mechanical (6.5L).

Sticky flow control valve.
Replace or clean the control valve. Refer to Variable Effort Steering System Check in Variable Effort Steering.

Insufficient pump pressure.
Refer to Power Steering System Test .

Faulty gear pressure relief valve.
Replace the faulty gear pressure relief valve.

 

I've seen a 98 have the same issue. The owner took it to the dealer and it was the steering position sensor under the dash

 

Almost the opposite, the steering seems appropriate most of the time but will occasionally become "loose" almost as if there is a surge of power in the hydrolics. So if I am turning the weel slightly there is normal tension but then for a half second it seems to over correct as if there were no tension on the steering wheel. It isn't that the actual drive wheels move just the steering wheel "lets go" for a half second