ive been hearing a "knocking" noise so i took it to the shop...it was the tensioner so it was replaced along with the timing belt, waterpump and a few other smaller parts. the next day it was still making the same noises so i took it back and they said all was fine. i now hear this "knocking" or "sputtering" noise but this time it sounds like it is coming from the rear of the car. ive never owned a turbo before so im just wondering is this a normal noise for the car to be making? during the summer the noise was never around but ive noticed as it gets colder and when the car is warming up i hear it. like i said the shop said all is fine..but still...what can i say...i worry!