We owe the inspiration to get the AIV valve out and serviced to Kitty47200 (sorry, haven't seen your names yet). They said they were doing that and had decent results.
Anyway,
The AIV is easy to do. We suggest NOT removing the whole assembly from the car. Just take a real hard look at it and find the 4- screws that hold the 2- halves together. Remove the small vacuum line to the top, the larger one, and take the 4- screws off. Pull the top half off and there is a kinda "cap" over the reeds. GENTLY pry the assembly out of the housing. There are 2-sets of reeds. We only did one at a time so we could see how they went back together. With a wire brush and a can of carb cleaner, all we had to supply was a little elbow grease.
A&W
'91 s13