These cars slow significantly just leaving them in the highest gear "D"....especially from speeds 45 or greater. If your driving 35 or below, just drive around all the time in "S" then it will slow you down even more when you let off the pedal. In residential areas of 25-35mph I often don't use overdrive, there's not really much point, plus the added drag/braking effect of being in third gear does help save on brake usage....
Our stupid minivan is a different story, if the surface is level or even a slight grade, its speed INCREASES as it rolls along, even if you don't touch the pedal, thus requiring braking on occassion, and complete brakes to slow from whatever speed. Needless to say, when its driven as a Daily Driver it eats a set of pads and rotors once every 1.5 years or so. Good thing its not a daily driver for us...
Oh yeah, check engine light on again too....
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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)