hi, i have an a3 1.8 sport, non turbo, its a 1998 model, chuffed to bits with the car, but lately i have noticed a problem, when accelerating as soon as the engine reaches 2500-3000 revs the car seems to hold back, and after a brief spell the car coninues on its path up through the revs normally, its almost like a turbo lag, only this car has no turbo, the car idles perfect and this problem dont seem to happen all the time and its not always on a certain gear, one moment i might happen in 3rd and the next it could be in 5th, i have no warning lights, its had a recent full service, any advice would be great as it is frustrating. thanks in advance