[5000SE]

Originally Posted by Katpee

I've seen quite a few threads on here about consumption and some have said that they coast (ie in neutral) whenever they can.
It's worth pointing out that when you are coasting the engine is actually using fuel to keep the engine running, whereas if you don't 'coast' the engine is actually more economical.
Sounds strange I know but give it a try it may help.

Fuel is still fed to the engine if you coast in gear - more than if you let it slip to neutral and idle.
Try zeroing your trip computer fuel consumption reading as you coast down a hill in gear, and see what figure it steadies at and gives you. Then zero it again after you put her in neutral and see what that gives. The former might be 70mpg, the latter could be 200 or more.
I have a 55 mile A-road drive into work every day, and I experiment to relieve the boredom. Driving gently and deliberately aiming for economy in gear, I can get a bit over 50mpg. By coasting in neutral at every opportunity, I’ve had it up to 56mpg, always over 54, and don’t worry about the safety issue of potential wheel lock up in neutral because of the ABS.