99 Civic Idle Air Control System

[Pawl]

143,000 miles - I noticed lately my cars idle goes up sometimes when I start it. I was shutting it off and starting it again and it would stop. Recently the check engine light came on and the car was running rough. I cleared the check engine light with an OB2 code device and it ran fine. Then the check engine light came on again. I have power to switch that clips on to IAC Air Control System. It is a rotary type IAC control valve.
When I started motor the idle was bouncing up and down. I took the electrical connector off and high idle rpm stayed up and did not come back down. With 143,000 miles on this car I am thinking the electrical part of the valve is bad.
When I went online to price it at an internet supplier both parts of the valve were shown together meaning to me I can't buy one of the two separately. They were not shown for sale separately.I was wondering if when it appears the electrical portion is working intermittently it is also the time to replace the rotary valve attached to it. Does the rotary valve wear out? It is a pricey two piece set to buy. $259. Any thoughts?