Hi i've had my car since july 05. its a tipronic r34 gtt with about 80K kms. It sometimes has a vibration or shudder thru-out the whole car. It does this every now & then, roughly once a month just for a few minutes. I can only feel it when stopped in traffic. The car is totally standard and i use 95 ron fuel usually. My friend who has a an 04 RX8 recently had this problem too.
Any ideas what this is?