Secondary air

If you have no trouble codes setting, there's no reason to suspect there's a problem with that component. It will just require more proper driving to get it set. If there's a problem, a warning light with trouble codes will set. Your rough idle is something that indeed should be addressed -- but it's too hard to know what the root cause of that may be. Fuel, air and ignition spark needs to be checked; emissions controls are important too - EGR function? www.repairpal.com/repair-shops