i have a 89 camaro. it has a 305 tpi engine in it. how can you tell when the idle air control is not working. how can i test it.

When you first start your car, the engine RPM's should be around 1500 RPM's and drop down to 600 to 700 RPM's in about 3 to 5 seconds. If not the IAC is defective or needs to be cleaned. Remove it and inspect it first before replacing it. I use a small wire brush and brake cleaner to clean the IAC. Then replace it and start the engine to check it. If the RPM's do not raise then drop, replace the IAC.