I just noticed a klanging sound on acceleration - seems to happen about 80% of the time I press down on the accelerator. Can't really hear it with the windows up - but with them down it is very noticeable, especially at low speeds. My VX is just a little overdue for the 30K maintenance, so I'll be taking it in soon. But I was hoping to get some sort of idea as to what it might be beforehand to keep the dealer honest. Any ideas as to what it might be - loose muffler perhaps?