Just wondered if anyone else with a 370 has this, not that its a problem just curious. On a cold start the exhaust note is decidedly rorty for about 15 seconds, then it quietens down to a smooth even fast idle. I have no leaks and the noise comes out of the exit pipes rather than a leak etc. I imagine its the engine management.. as I said no issue and the cars only done 12,000 miles etc and running a standard exhaust sytem....just wondering.