low idle?

[98COBRA281]

it started the other day, it usually idles around 900rpms on my gauge, but now it has been down around 600-700rpms when warm. i dont like it that low because you can barely hear it at 900 it has a nice rumble to it, could it be the iac, should i try to clean it, i had the car for almost 2 years now and have never changed it.

 

[the98stang]

First try the IAC. If that doesn't work check out the plugs.

 

[98COBRA281]

First try the IAC. If that doesn't work check out the plugs.

the plugs dont even have 8k miles on them, and about 1 month ago i took all of them out to check them, and retorque them, is there any way to adjust the idle?