i recently purchased at 1987 Mercedes 300e with 118000 miles on it i haven't put it on the road yet, however start it regularly. I have had no problems till today. After starting it and letting it run for a couple of minutes it begins to shake and rattle and then shuts off. It has half a tank of gas and all the fluids are OK- oil, power steering, antifreeze etc...Any help would be appreciated. Thanks