As you’ll no doubt know. My 2009 S4 is new to me and has had this annoying lumpy tick over thing at ideal. Plugs fine, coils fine and a lot of owners say it’s normal. So I thought I’d just live with it. However, for the hell of it I stuck a can of this 44k in the tank and also did the old foot on the floor ignition throttle reset thing ( not sure if that even works on b8) and have been using it very sporadically over this past week where it’s had lots of time to sit and let the additive do it’s thong. I’m no mug. But one of those 2 things has completely changed the car. Smooth idle, free revving and so much more alive. Hopefully it might help others but for £15 why not!