I have figured out at least one cause of the s3 flashing or blinking light on the drive selector panel. 1989 legend 4 door. I get intermittent s3 flashing. Solved problem by pushing hard in the spark plug wire sockets that attach to the spark plugs themsevles. Sometimes under hard driving or cornering, the spark plugs wire sockets pop out about 1/8 to 1/4 inch, which for some reason is enough to cause an error message to cause the s3 light to flash. I can make the s3 light flash at will, by slightly pulling out one or more the spark plug deep well socket (the part that actually attaaches to the spark plug). Apprantly after market spark plug wire kits do not have the rubber knurl necessary to make for a tight fit between the wire and the aluminum deep well spark plug cavity. hard to explain, but if yo uhave ever replaced the wires you know what I mean. I think this problem is the cause of several s3 flashing light problems I have seen before on other forums. Seems their problems go away when they do a tuneup. Also, after puhsing in the wires, the engines smooths our very nicely. my guess is that the spark has to junp an extra 1/8 to 1/4 inch to just to get to the spark plug tip, and so the resulting spark is very weak, which results in incomplete combustion and a resultant irregular power. The engine vibrates badly to very badly, as sometimes more than wire gets popped out at the same time