S500 4 matic dies randomly on acceleration

I'd really like to buy my friend's 2003 S500, but he's reluctant to sell it to me because it has an intermittent problem. Apparently, every now and then it will completely die when accelerating away from a stop. I've asked them if there's any consistency to it, but they say it is totally random. They've had it to two dealers, but neither could find a problem.

My guess is that it's the drive by wire system. Is this a known problem to anyone here? Any ideas?

Thanks

Most likly a crank sensor is failing. Need to have it removed and tested. I have had to replaced HUNDREDS od these on 112 ans 113 engines. The will not leave a code, just cut out and the engine will die, usally when its hot.

thanks. he decided he was too nervous about it and refuses to sell it to me. he's trading it in. i'm sooo mad. would have been a great car, and all he wanted for it was what they were going to give him on trade.