Thanks Joey. Yes the steering is difficult but being an old guy who grew up before power steering I did just fine without it. I believe the most likely cause was a sticking valve. I don't want to start throwing parts at it until I can determine what the source is. I will check the screen when I flush the rest of the fluid. Also wondering if the old fluid had reached it's useful life and may have been a contributing factor. The belt tension is good and the belt appears to be in good condition. If I do have to change out the pump eventually I will change it since I'm in there already and have it off the pulley. When it was giving me problems I did notice a higher idle than normal up to about 1500 RPM. Could be the system was calling for more pressure if the valve was sticking. When I tried to test the switch it was on jack stands and probably didn't have enough resistance to call for more RPMs. It still seems to be driving fine so I will keep a close eye on it and now that I know a lot more about it if it does give me problems in the future, I should be better equipped to diagnose the real problem. Thanks again for all your help!

 

Dirty fluid could be a factor. Had a few issues with a intermediately stuck PS pump relieve valve making steering extremely challenging!!!!

After removing/replacing the PS fluid until clear again (via numerous reservoir fluid changes) and keeping it clear, the problem went again.

Could also be built up debris in the reservoir.

The PS pump switch appears to be either ON/OFF. With a prolonged high PS system pressure and the switch now ON. An increased engine RPM to compensate for the extra PS pump loading would be logical.