My only slow car symptoms was fixed from the banjo bolt at the back of the intake being clogged ,onced cleaned out it was a new car. Oh ,forgot about the linkage piece that hooks to the injection pump ,thats another one ,if the piece is loose with play the rolling jointed piece on the assembly is rotten,made of some hardened rubber that deteriates over time and wont give you the correct throw a new one gives resulting in slack from foot peddle to rev on the rack of the injector ,easy fix and easy to look for as calpriets,just wiggle the rod coming to it and if theirs play it needs replacing .I would add fuel lines into the replace catagory items ,rubber lines maybe restrickting flow internally,had a 190e with this issue and of course filters including the tank screen.
This car was being sold out of Houston ,correct ? Thats a good deal for a running car ,not to mention a wagon ,did you get the coil spring compressor he was also selling w/ the car?