I checked the operation of mine and it is not consistent when turned throughout its range. While it is not horribly bad, if is not smooth and consistent either.
I will be opening it to see if it is worth modifying it as described in the book (depends on what resistance strips look like inside).
My new question is that the book says “same resistance as the original at both ends of its travel (from .05 to 3.5K ohms)”, yet mine reads reads 4.7 to 5.0k ohms at spring stop idle position, and .25 to .30k ohms (250-300 ohms) at full WOT position (showing some of the inconsistent readings).
In the meantime, I ordered the Ford TPS part number, E7DF-9B989-AA, shown in the book.
Less expensive than the original or the red replacement by a factor of 10. Cheap enough that if the resistance range is not as stated in the book, it’s cheap enough to keep just to see if I can do anything with it (add a resistor in series if too low resistance, or maybe add another pot in parallel to play with it if the resistance is too high … it has been a lot of decades since I played/worked with individual parts in circuits calibrating and repairing oscilloscopes, voltmeters, signal generators, and all kinds of other stuff in a Standards Lab at a defense plant.
I’m one of those people who buys things, then alters/modifies/(sometimes even Frankensteins them) those things so I can use them for what I want/need. Thus the “I decided to cut off the 4 contacts, shorten them by about 1 mm and resolder them” rekindled my senses and thinking.