Hello.

I recently bought a 307 SW auto and it had exactly the same faults as you described. Fortunately we noticed the problem before we bought the car. On collecting the car we were told that the fault had been rectified but unfortunately it hadn't. The car was returned to the garge and the fault has been rectified by changing the exhaust manifold and gasket. I have no idea what could be wrong with the manifold to cause the problem. I can only assume that the gasket and manifold were leaking in air, when cold. When the engine warmed up the air leak dissapeared.

Good luck!

ps if you ever need new front brake discs & pads... I just got some on Ebay for £41 delivered!