Hi Everyone! I'm hoping to find a bit of assistance with my 2004 Cooper S. I recently believed the fuel pump had gone bad. I took a chance and replaced it. Immediately after the swap, the car started right up and has started every time since. However, when I test drive it, it has this odd vibration and relatively loud knocking noise (not like an engine knock; I can feel it in my seat) when I accelerate, and it's sluggish. There's definitely something wrong with it. None of this happened before the swap. Any thoughts?

Thanks!
Chris