I've been having the same problem too: (A kind of loud noise by pressing accelerator to take-off ahead...Meanwhile! it kind of feel like slower to respond when pressing the gas pedal and making (an very heavy noise Brouuuuuuuuu) on take-off. Otherwise, I dont have any kind of vibrations like you guys mentioned above, except of a slight sound of my fan running which is normal, and I think I would even beat alot of BMW's owner on running smoother.
Instead! I think it would be an "Exhaust leak" Once I already know that my X5 is missing 1 bolt on each side muffler pipe since I bought it. So it would be a good possible reason to make me think with an exhaust leak.
(01 X5 4.4i)
Think you runs smoother than me! I dont think so
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