misfiring on new spark plugs

What is your question?

so my passat wagon had new plugs as well as wires replaced approximately 6-7 months ago. as of recently, she started running rough again.... after i start the car and let the idle drop, the car starts to shake/run rough. the check engine light is on and the sensor reading/diagnosis is misfire in the 6th and 3rd. if i let the car continue to run after starting it, it eventually (w/in 2- 3 minutes)stops shaking/running rough. it seems that the car runs fine once it is warmed up. my mechanic does not beleive that it is an air issue and he doesnt believe that it is the ignition coil. but i will add that there is an appearence of oil on the plugs.