I had a poor idle, it ran about 1000 cold to 1250 warm most of the time, cleaned the trottle body, noticed my TPS was not switching at all. I checked it with a ohm meter, no response at all, it had failed after 231k (RIP).

I have an 86 240 in the yard I picked up (engin siezed totally, no oil) so I went five feet to my right to the local pick and pull :) and pulled it off.

The numbers on the case are a little different, they look the same, and FCP groton sells the same swich for both model and year engines. My question is, does the TPS only switch one side of the three pin connector (this one clcks properly and swithes one side to ground at idle. The car now idles at 750 some of the time, some of the time it will hunt up to 1500 and back, esspecially after bumping the throttle. When the car is not running I swear the swich is working properly. I think I have some other gremlin. I've cleaned the body about 5 other times, the gaset is pretty good, I replaced most vacume hoses a while back. It's like a 50 50 thing, sometimes good, sometimes bad.

Am I using the right swich?
Is the TPS only concerned grounding the center pin to the left pin (held in your hand with the connector up, throttle body behind the switch) On this switch it is Pin 2 to pin 18 (center). The other pin does nothing. Is this correct?

I havent pulled the Idle control valve yet, I pulled the supply hose to it, closing off the air supply with my hand and the car died (did it several times).

I've been through the FAQ, but I am not finding the pattern for this issue. Any thoughts would be appreciated.
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89, Gold 745 GL Wagon, 210k known miles. Just a beginner