That's the "micro switch", which has to do with fuel shut off on overrun. There's also a switch on the rear side of the throttle valve shaft below the fuel distributor. It's connected to both the EZL and ECU via a three pin connector that is under the air cleaner on top of the inlet manifold and easy to access. One is ground and the other two are system voltage for the EZL and ECU.

I had a similar high idle problem and checking continuity at the connector showed that the switch was not working. It appears to be very difficult to remove due to its location, so my first "fix" was to thoroughly douse it with electrical cleaner. That got it working again and idle control has been normal for many years.

Duke