W210 M111 engine need advise
 

I have 1996 E230 (W210). My car ocassionally idle erratically at a stop. Another problem is sometimes my car failed to pick-up speed instantly after hard braking. Acceleration from stand still is OK but not after high speed braking as mentioned. This only happens recently. Besides this 2 problem, I'm very happy with the car, no engine oil leak and very clean. Mileage done 62,000miles. Thanks