Originally Posted by jaze55

I had this exact issue, cleaning the MAF and replacing the air filter made no difference. My car had approx 75,000km and I read that the G37 guys also experienced the same issue along with rpms dipping when coming to a stop. Affected high mileage cars.

Fix is to clean the throttle bodies, specifically the plenum side. I was surprised at how much carbon was built up. After cleaning, the car starts up like a beast and no more rpm dipping.