What I'm seeing is related to engine temperature, not ambient temperature. There is a factory "tool" that tells the ECU ambient temp is 20°C... check out the last item in this screen shot:

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=23I0RAMEE23Z0RGH3T&year=1994&make=MB&model=E-500-001&category=C&part=Air+Temp.+Sensor

Could it be taking off in 2nd gear? When it works correctly the up**** delay forces a first gear take off and holds first and second gears to almost redline. Perhaps you have a bad bowden cable?
Mike

It could be imagined but I feel as if my 4.2 is faster once Autumn arrives and the temperatures dip.

Nope, at least not on my car... I have the BergWerks FGS kit and I can tell when it's starting in 1st or 2nd.