Hello and welcome to JustAnswer!
The power steering pressure switch is on the steering rack. It senses the pressure in the system, and when the pressure goes high from turning the steering wheel, if you are at idle it will raise the idle speed slightly. you may not even notice that it's not doing it anymore. This isn't an uncommon problem on these cars. It's very likely that you'll need a new switch. It threads into the back of the steering rack and has a two wire electrical connector. It isn't expensive and it isn't hard to replace.
How immediate is it for me to replace the switch - I am going on a trip tomorrow and don't have time to take it to my mechanic before I leave.. (trip is 250 miles round trip - mostly freeway)
And you don't feel I need to have my emmissions regulator valve checked for a clog? The only reason I ask is that the owner's manual has a Caution! box in the Malfunction Indicator Ligt paragraph that says:
Prolonged driving with the Malfunction Indicator light on could cause damage to the emission control system. It could also affect fuel economy and driveability. If the Malfunction Indicaor light is flashing, (it's not) severe catalytic converter damage and power loss will soon occur. Immediate service is required.
I appreciate your time and patience with my questions. I am a woman who does not want to be taken advantage of by mechanics, so I try to research as much as I can on my own. I will definitely have the power steering switch replaced when I return from my trip.
Thank you kindly for your help with this matter! :-)