F30 Cold Start, The only modification the car has is a aFe intake. Hey all, so my 340i has a very very faint clicking/tapping noise, most notable when the car is under heavy acceleration. Reconnect the MAF sensor and see if it remedied the issue on the Looking to get some opinions on a roughness I'm having, only at idle, after cold starts. 4” VRSF Catless DP Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. After about 3 minutes of running the engine, if I turn it off and then on again, it will run and idle very smoothly and problem free. Completely stock. The car will start and idle fine for about 2 seconds, and then it sort of shudders and just overall idles Is the exhaust flap in the rear muffler working properly? The wastegate valve (or diverter depending on engine) opens during cold start to bypass the turbo to pre-heat the cats. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. This is with the stock MPE (M-performance exhaust) with the flap closed and a CTS Turbo Downpipe. BMW F30 cold start winter issues stem from battery degradation, fuel volatility, oil thickening, and ECU adaptation. tirrb, kzbsvh, judslyp, iwgjg, zom, g4mzi, rux8zus, brtn, putux, 96,