Whilst many suffer these sorts of problems, I don't believe it is how it should be. My M103 (with 184,000km) starts perfectly cold, hot or anywhere in between (I probably should not have stated that, something is now sure to go wrong). This is despite the fact that I have not replaced any ignition components (other than spark plugs) or fuel components (other than fuel and air filters) in the more than six years I have owned it (I have no reason to believe any other ignition or fuel components have been replaced in the life of the car). I can imagine the frustration of having such issues, especially in Rick's case where he has already checked and replaced so much. I would also tend to agree with checking the base mixture setting before the O2 sensor takes over.

My 2.3 litre M102 (with 226,000km) does not start or idle as nicely as my M103, although it is not bad enough to be annoying and once running drives perfectly. Even a 1.8 litre M102 with only about 30,000km I owned several years ago was slow to fire up and rough immediately after starting. Obviously the KE systems are somewhat variable from one car to the next and it does not take much for them to be a bit cranky. A shame really because I believe the M103 to be one of their sweetest motors.

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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.