i had the same problem with my r32...try changing your spark plugs and if that works your lucky...but if the noise doesnt go away it could be your coil packs.
iv'e had to to change all 6 of mine in the past year and its a bit of a bitch cause it could be one of them thats damaged or all of them. The problem with coil packs is you cant physically see which one is the damaged one. At about 200 bucks each my best advice is to replace 2 go for a drive and see if the noise has stopped. if it hasn't jus keep swapping the new ones around till u find the damaged one. Worse case scenario is they're all damged and you'll have to buy 6 new ones like i did....good luck mate.