We kinda had a problem with our 88 300SEL a couple of years ago... turned out that the coil had went bad. It would run OK until you hit the gas, then it would bog down, stutter, and sometimes stall out. We tried a host of things, but turns out a new coil took care of it. We had actually used the one off of one of my old Chevys just to see if that was it and it was. We when went and bought one of the cheap ones at Autozone and its worked fine for 2 years now. Not sure that is what is wrong with yours, but may give it a try.

Good luck!