Shudder under acceleration

Hi all,

I just noticed that the car has a brief shudder (like a rattle) that comes from under the center-rear portion of the car upon take-off. It only does it on take-off from a stop somewhere around 10 mph I think. This does not happen during turns etc. only from a stop going straight.

The car is an '04 325xi - very carefully maintained. Any common problems that would cause something like that?

Sounds like you need a tune-up: plugs, fuel filter, air filter, scan codes and fill it up with 93 v-power.

Seriously? I'm quite sure this is metal on metal rattling.

There is no way this car needs any of the above. Spark plugs I did at 90K, fuel filter at 120, air filter at 120 and the car has 133,xxx miles on it. And the car always gets Shell 93 or Chevron 91 when it's in Arizona for the winter.

Is the feeling like a clutch slipping?

I find that my car (non AWD) will have a similar feeling when I launch from stop and hit that "middle ground" before the clutch fully engages.

The car is an automatic.

It's coming from the REAR of the car. I'll figure it out - there's probably some sort of mount that's broken back there or exhaust hanger/bracket - I'm just not too familiar with the common causes of these sorts of vibrations on BMWs being a Volvo guy and was curious if this was a common noise with a known fix.

I had a shuddering when coming of the clutch and I also had a small rattle. The shuddering ended up being a very back front control arm bushing it would shudder when the wheel started to get load from the clutch. This also caused some serious pulling under hard braking.

The rattle I had is how you described exactly, I would was also hear it when I shut the driver door. It ended up being a heat shield up near where the headers come into the exhaust.