2008 Kia spectra ex 60k rough idle when warm no cel

[bcrpc1]

We have a 2008 Kia spectra ex 2.0L auto with just over 60k on it bought it with 48k on it. We have done oil every 3k replaced the plugs with irridium ngk plugs at 60k and idle was good for a while also changed pcv valve. idle was good then rough again for no apparent reason. Checked for vaccuum leaks as well as cleaned the throttle body too. Is there anything else i may be missing on this as a cause of rough idle no loss of power and good mpg could this be plug wires being orig or the air filter looks like it is sucked down on one side in the place where it seats in the air cleaner assembly?

[bcrpc1]

Changed air filter it helped a bit just wondering if plug wires may be suspect at this point as well as gap of the plugs if the irridium plugs can be gapped? i did not gap them was told i did not need to before i put them in