How do u check a 1991 ford mustang IAC ?

Question

I want to test it before i buy a nonrefundle part

Answer 1

You can't really test it. The engine vacuum and controller do things that you can't copy. What is the problem?  

Answer 2

you can tap on it with a hammer if the engine idles down the iac motor is sticking  general problem with all fords you can clean them with carb cleaner alla the carbon will come out  and iac motors are noe vacuum controlled