An FYI for anyone interested. About 10000 miles ago I had the engine out of my 94 SL500 and went completely through it. This overhaul included all new ignition parts, caps,rotors, wires and plugs. On the advice of someone who supposedly knew I put in the Bosch Platnum+2. (Two ground electrodes with an open end gap). The reasoning given was unshielded spark and all the other irrelevant BS. The first 6 or so thousand miles I was still working and never made short trips. After retirement trips to and from the local market etc became routine. I found that the first trip in the morning, if I did not go far enough to accomplish a full warm up, when I shut it off long enough to go into the store, on restart the engine would miss horribly and I would need to carefully nurse the throttle to even get it to move. After months of checking everything I could think of, even so far as to carry my dvom with me and check temp sender and ambient sender values cold, partial warm up, heat soak, full warm in parking lots and checking everything I could think of in the ignition system I changed the spark plugs to a "standard configuration" plug. As this was an experiment I did not even get platnums but the cheapest thing I could get. PROBLEM SOLVED The car idles and runs better, the fuel economy is noticeably better and most importantly no partial warm up engine miss. I have not fully digested the cause and effect but I would guess it is probable that the gap, approximately .080 on the end gaps which is non adjustable is more than double the factory recommended .035. Whatever the reason I just thought that I would share the experience if anyone else runs into similar problems.