I have a 1987 MB 190E. It seems to due this only after a cool down for at least maybe 15 minutes. When you get in to start out it goes fine for about a block or two. Then it starts to fall down and idle very rough. It will keep this up for a good while and then it will start running smooth again until you shut down again. I have replace the plugs, fuel pump, filter, ignition cables etc. Can you possible tell me what the problem might be or where to search? Also, where can the repair manuals on cd's be found? The car only has 50 K miles on it.