Hi guys! My Passat 1.8T's engine has had this noise since I got the car, from used, 2 years ago. I hear a sort of a clatter/rattle when I blip the throttle..... (First I thought the sound was linked to the turbo as it goes away once the engine is fully warm or the turbo is boosting, or revs are higher) . However this seems to not be the case. The sound seems to be coming from the rear of the engine where I see a lot of hoses and a vacumn component or two. Can anyone shed some light? Also, have just replaced the MAF as it had failed. Now when I start the car from cold the idling sits at just above 1000 rpm for about a minute and then drops down to the right level of about 800rpm. Also, since the new MAF under light throttle the car seems to hold back at about 2,500 rpm and then pulls well. (Does not do this under medium to heavy throttle). Car has Usolute chip and freeflow exhaust.