Any advice is welcome, the dealer has tried twice to fix the problem with no luck.

My wife's ML320 (2000) occassionally won't start after she's driven somewhere and parked it for about an hour (45-75 minutes). When we turn the key, it cranks ok, fires for about half a second, and dies (and gives a 'start error' i think).

If we keep trying to start it in this condition, it seems like we burn out the key
after a while, and get 'start error' on the dash display, and that key cannot be reprogrammed by the dealer, we have to order a new one.

If we wait an hour or two, or sometimes if we remove the gas cap, then it starts and runs fine. During the winter, we never have this problem.

We've had this happen about 10 times, and twice we've burned out both remote keys (probably because we tried both keys many times).

Is a key likely to burn out if you try and start the car 30 some times in a row in 3 minutes?

Is vapor lock something I should be thinking about, and what's a good solution?

Rich