Cutting out when idling - Merc C240 - Puzzled
Car is a Merc C240 auto (fuel injected, of course). Done 104K miles, mostly trouble-free. I do about 58 miles a day, back-and-to to work, virtually all on dual carriageway (50-70mph).

It\'s developed a habit of cutting out unexpectedly. While this rarely happens (only three or four times in the last 3K miles), it\'s irritating. It has only ever happened when I\'m in a queue, and when the engine\'s about three quarters warmed up. Typically, I\'ll be stopped, foot on brake (selector in \'drive\') and the engine just cut out, all dash lights on, and no engine. If I select Park, switch off and restart, the engine starts again instantly. It cut out this morning, but on this occasion the engine was nearly up to temperature and it took about three or four seconds to start. whatever, on every occasion, the car\'s worked fine afterwards - until it happens again.

Last Monday I was stuck on the A2 for about two and a half hours, moving at less than walking pace, but it never cut out once - but of course the engine was at working temperature. There\'s no problem with overheating, by the way. I don\'t use cheap petrol, and never have done.

It has always started instantly after being left, whether from freezing conditions overnight or after the weekly trip to Tesco\'s.

It\'s serviced regularly by a specialist (and before the mileage got so high by a dealer).

Naturally, I don\'t want it to cut out and get stranded because it decides not to re-start! What could be wrong? And should I be worried?

Any ideas would be welcome (apart from buying a new one!)

Cheers

Richard