Cant really describe it perfectly but i'm sure one of you will know what I mean... when I drive the car with warmed up engine in 3rd 4th and 5th gears with very little steady acceleration, the car does a small but very noticable 'chug' as though the fuel over run cut off is activating for a second causing the car to ever so slightly buck........ should I be more worried than I am embarrased lol No warning lights on and car is 2.2 petrol SRI z22se (53 reg) cheers