My 1990 560 SEC holds upshifts from 2 to 3 and 3 to 4 for aproximately 60 seconds. This happens until the car is up to operating temp, then the car shifts as normal. I have read and been told that there is an exhaust temp sensor that delays the upshifts in order to get the catalytic converter up to temp ASAP. My question is can this sensor be overridden, or at least re-calibrated to shorter delay? Any replies, and or advice will be greatly appreciated.