I'm new to Mk5 and i've just been underneath the car and replaced my knacked (for a while by the looks of it) rev B dv for a secondhand Forge DV. I also replaced a couple of the ic pipe seals. Basically it runs like crap and I've double checked the vacuum hoses and plumbing and it's all correct. I'm going to take it out for a steady 20min run to see if it's a case of the ecu relearning