That would worry me a bit, the unexplained use of an epoxy that is. Is it by chance on the top side of the manifold close to the connection for the flametrap? That would be the redneck way of closing off the vacuum line to the Ignition Module. Hopefully that's the reason not trying to fix a crack in the manifold.

For sure you want to give the Idle Control motor a good cleaning and lubing up along with cleaning the whole area. Use a light oil (not WD40) to lube the bearing after you clean it. It should spin freely when you spin it. You are most likely going to find a oil soaked area right there at and in the throttle body. Do not use the throttle body cleaner on or near the AMM. CRC makes a cleaner for it or leave it alone. One warning to pass along, the easy way to remove and clean the motor is to unbolt at the top and then from the three bolts down at the bottom of the braket. Those bolts down at the bottom are actually connected to the topside of the motor mount. When you take the bracket off put two of the bolts back in there and start them. I did not pay attention to this and my motor mount at some point slipped over. Ended up having to pull out the jack and line that back up. Just don't want you to make my silly mistake.

Any leak of air after the AMM is going to cause some sort of idle issue from running rough to a surge. A good thing to do take the intake hose off the AMM and Throttle Body and check all over for splits, cracks, and holes in hoses and lines. Then you can remove the IAC motor and clean it along with inspecting the hoses on both ends. If you pull the throttle body off go ahead and replace the flametrap and clean the breather box. It is just below the throttle body and you will be able to see and reach it. You will need an oring for under the breather box, and a gasket for the throttle body. When I got started working on the idle on my 86 it turned into a three trip day to the local Eurohouse. Ended up with a new flametrap, throttle body gasket, intake hose, cleaners, two sizes of vacuum line, and a new oring under the breather box. But after a day of cleaning and replacing stuff found that a 245 will sit there with a smooth idle.

Good Luck,

Paul