i know its a stupid question but iac stands for idle air control valve correct thanks for baring with me in my stupid moment
also for everyone else because i know theres alot of people bein told to check theres can someone leave a educated definition of what it does

 

it introduces air into the motor so it will idle when you push the gas pedal the plate in throttle body takes over

 

it regulates the air flow at idle

 

it wouldnt in no way cause a slight knock in the head would it

 

no it wouldnt

 

not that i know of if your hearing a knock or tap in the valve cover/head it my be that you have a rocker arm thats come loose

 

thanks guys for baring with me i know all this stuff as it was drove into me in school but i havent worked on much n a few years and i tend to forget things after im done using but i have a rough idle and was thinkin it was iac and i to think the knock/tap i got was a rocker,pushrod,or lifter but havent opened the valve cover

 

let us know when you find the source of the knock