Hello, I just did a fuel filter change about 2 weeks ago. I don't see how this would have anything to do with it, but I saw it mentioned in a few topics while doing some research. Since about 2 days ago I noticed that the car was slightly jerking at lower speeds. And today the engine light came on. It gave one code: P0401. After reading through the forum, there seem to be too many possible causes to this problem. I need some help as to where to start. I have no clue where the EGR valve is located or where the PDFE sensor is. Any help would be greatly appreciated.