just noticed today, it happened twice that the car have 'jerked' when the car was at low-gear (from a stop-to-go).. the car was on "S" every time. I set it on "C" and so far, it haven't done that.

car is at 73k miles - 2006 C230 SS..

bad coils? plugs? alternator? battery (haven't changed battery since bought CPO on 07), transmission problems to watch out for? (haven't done transmission service).

thanks in advance.