I have a 2003 Mini Cooper, base model. Manual tranny.

I've only owned this car for about 4 months now.

In the morning the car will have a fairly high idle... I'm guessing this is a warm up process. Either way, it'll feel like it's losing power. Sometimes it'll stall out and die, but will be fine afterwards.

HOWEVER... sometimes when I stop at a stop light it'll start to bog down to aroudn 500 RPM until I blip the throttle.

Also, almost every time I start moving, the exhaust will rattle like crazy. I've checked it and it doesn't seem like anything internal, but it's disconcerting nevertheless.

My gas mileage has started to steadily drop as well. I used to get around 30 miles a gallon, but now I'm getting closer to 26.

Any idea what may be wrong? I have about 86k on the odometer. I figured it may be a belt issue but the belts seem fine and they aren't loose. Powersteering is fine as well. I'm stumped. I haven't taken it into the dealer yet since I work quite a bit, usually from 6 to 6. I'm gonna change the oil soon as well, but I seriously doubt this is a problem.

 

O2 sensor is where I would start.

 

You might want to consider getting the plugs, air intake filter and an oil change. Sounds like you need a tuneup to me.

Did you ever get the serpentine belt changed? If I'm not mistaken they recommend getting it replaced every 65-70K. It might be slipping.

As for the exhaust, it's probably a heat shield banging around or rusted up. 02 sensor may be a the culprit but I would start with the basics.