I own a 2008 E320 Bluetec and about cruise control I have heard many different opinions about fuel economy while driving in highways.
I would like to hear from people in this forum if: technically speaking cruise control help to save fuel and if cruise control helps the engine and transmission to run more efficiently.
Driving in cruise control I noticed that in downhill where the car tend to go by gravity only, the engine seems like to hold the car to NOT to go by gravity because cruise control maintains the car at certain speed ignoring engine RPM.
Please share your thoughts about that. I want to learn more about this.
Thanks

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Nyck - TX - USA