I just picked up a 2009 128i with 80,000 KMs. The previous owner lived on a farm, and most likely ran farm gas in there which isn't filtered as good as the gas station gas. I have noticed that at idle there the engine is not exactly smooth. There is just a bit of roughness to it.
I am going to replace the spark plugs, and I want to replace the fuel filter, but I have heard that there is a "permanent fuel filter" and that it is in the tank. I think there has to be a way to replace it, and I am hoping that someone here might have done it before, or have some info.
I have ran some sea foam in the tank to clean things out a bit that helped a little. I have seen fuel filters cause a rough idle before, and new plugs can't hurt. I can't believe that car companies put filters in the tank
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2020 X5 M40i, and 2017 340i M Performance
Previously owned
2009 128i, 2004 X3, 2008 128i, 2007 X5, 2012 328i, 2015 X3 35i, 2015 228i