My 86 635 auto NA has been running rich and failing smog.100k miles.
For the last 18 mos I have been trying all the usual suspects but I have a specific TPS question.
I have the 86-88 TPS under the rubber boot.
My car per backprobe is running .9 lambda should be about .5 lambda.
I am checking not the idle switch ( clicking properly ) , there are two on the 86-88 autos, but the full throttle switch.

I checked the terrific website http://www.hiperformancestore.com/Motronic.htm ( step 11 ) which says and another website confirms this:

------- Now measure voltage between the yellow wire (terminal 2) and the brown wire. Voltage should be about .7 volts with the throttle closed and increase as the throttle opens to about 4.78 when it's fully open. -----

I am NOT getting these voltages with the key on as directed.
I am getting 4.37v at idle and it decreases to .68v wide open.
Adjusting the two screws in their elongated slots completely the other direction gives me:
3.59v at idle and .75v wide open.

What I'm worried about is that the TPS is stuck in the full throttle position which enriches the entire system to about .9 lambda.

Anybody have an idea what's happening here?
Thanks,
Jim