On my way to class today I was on the highway cruising at about 65mph. All of a sudden my car stops accelerating and the gas pedal is not responding. I was in the second lane and barely got off the exit. I had to roll to the side. I then heard loud rumbling from the back... Maybe the exhaust? I restarted it and it drove normal again but now I hear rattling coming from the back of my car... I'm at 104k miles what can this be??!?

 

That is scary !!

Does the MINI have an accelerator cable or is it "Drive-by-wire"?

 

I would guess exhaust related problem too, maybe catalytic converter is shot ?

 

Kinda sounds like a chunck of your cat dislodged itself momentarily blocking the exhust causing the initial power loss, then repositioned itself in back near the resonator...

 

yeah, maybe. but it is still rattling

 

Any codes thrown? A bad cat will usually throw a code.

 

It is drive-by-wire.

 

At least your already have an aftermarket cat back so you should be able to access it via the rear clamp.

 

It not a perfect science with these things. Have seen chuncks of the ceramic inside crack and break off creating all sorts of accelleration issues and not a code present.

 

well i have been getting an intermittent "SES" light popping up. Don't know if it's from this problem though. Usually when I first start driving it bucks really hard. That might be a whole different problem on its own though...

 

Yup...that's why I said "usually".