1992 ford ranger code 212 ( loss of IDM signal/ SPOUT circuit grounded)

Mr. Danner,
First let me commend you on your deductive reasoning and elimination skills, wish i had your knowledge. I'm reaching out to you because I have a problem that has been plaguing me for about a month and a half now that no one can seem to fix. I have a 92 ford ranger xlt 3.0l v6 that recently had a 97 taurus 3.0l v6 engine put in it. Everything went well and it starts and runs...but the check engine light comes on and stays on...I ran the code with an ODB1 reader and it's a code 212...I looked up the code in the code book that comes with the reader and it says  (Code 212 - Loss of IDM Signal / SPOUT Circuit Grounded)...I have no clue what this means since I'm not a mechanic. I can't find anything about this SPOUT circuit or how to test it. Tests for spark to testing all of the engine ignition components, to the pcm have been done,  checked wires for continuity to ohm readings have been done also.  the only thing that i did find was that i couldn't get an ohm reading from the IDM signal wire. I was told there is a resistor on that line (22k ohm), yet i couldn't get any reading from it nor could i find this resistor in the harness. As i stated, it starts and it runs, but it does have a rough idle and it hesitates a little when you rev the engine and to me a slight misfire. I'm at a loss so i'm reaching out to you to see if you have any incite on what you think it could be before i do the "throw parts at it" mistake. It has a new pcm, new plugs, wires, distributor cap and rotor. Only thing that i know hasn't been changed or it's been a while since it's it was changed, is the ICM and pick up coil in the distributor. Any help you can provide or point me to one your videos that might help would be greatly appreciated.