09AudiA42.0

Okay guys I needs some help.
my 09 audi a4 2.0t has a misfire at low rpms only.
if im driving down the road it has no misfire,but if I stop,or im in park or changing from drive to reverse it has a misfire.
cel codes- idle air control valve, rpms higher than expected at idle,multiple cylinder misire,turbocharger/supercharger underboost.
car has 140k miles a friend practically gave me the car and im new to foreign cars.
so far im replaced plugs and coils
denso iridium tt spark plugs and the coils were what the vehice called for from advance auto parts.
any help would be greatly appreciated!!!
thanks in advance!!