Exhaust Note Changed...

[Guest]

Hi all, got home from work and on the last part of the journey I pulled up at a roundabout and thought "jesus that chavved up Vectra 2 cars back has a throaty exhuast on it", pulled up outside the house and realised it was my car! Also there was quite a hefty "hot" smell from the car and at first a slight chemical/metallic tinge to the smell.

I stopped the car, went in, got changed, came out, started it and the note has gone back to normal. Any ideas?

My first thought was the cat..... *gulp*

Car is a 1.6TDCi Zetec S.

Thanks

Paul.