I have recently purchased a 1989 MB 560SEL with 290k miles and the odo has stopped working but the speedo still works. It runs remarkably well for it's age and mileage. I do not have a history on the car. I am driving the car almost daily and it still has good power and the transmission changes flawlessly. I have replaced the gas pedal and gotten an oil change. The only issue I have is that it idles a little rough. Almost as if it is misfiring but I think it's a fuel issue. I have ordered a fuel filter. I don't know but I would assume that the engine is choked when it is cold and it doesn't start idling rough until it's warmed up. So I am replacing the fuel filter as a first step to curing this issue. I don't the date of the last tune up but there was a used set of wires in the trunk which tells me it was either recently done or maybe someone already tried replacing the wires to cure the misfire. Any suggestions?