Most likely a big leak in your exhaust. That should be it.

 

flex pipe is a good call I did the same when I hit a rock and it buggered the flex up

 

Thanks for all your input...I took it to a mechanic and they discovered that the bolt that coonects my Turbo to my exhaust somewhere under the car was loose for some odd reason...so all they had to do was tighten itand that solved the problem. I was so relieved, I really thought i was really screwed moneywise.