As Diseasel300 stated, it is usually cracked solder connections that are the source of problems with that idle control module and they are usually around the leads of the rectangular capacitors (pink, green and blue ones in your first photo). You usually can't see the cracks without removing the lacquer conformal coating that coats the board.

Electrolyic capacitors can also be a problem at that age. You have 4 radial and 2 axial on that board.

I have probably fixed 25 of those modules and have never needed to change those small transistors. Once I had to change the larger one under the metal clip because it was roasted from a shorted idle solenoid.