Today, for the first time in a long time I had a long journey to make and no particular rush to do it in..... so an MPG experiment was in order. The test is in no way definitive but I thought the results were quite useful (all driving is highway).
Economy drive: Lights off, cruise off, climate off. Light throttle and coasting when able. Average speed 60mph. MPG 50.1 over 25 miles.
Cruise on: not much difference on the level but huge difference up hill - cut 10mpg from what I could manage with my right foot!!
Climate on: cuts about 8mpg.
Lights on: no discernible difference.
: Full throttle when able, cruise off, lights on, climate on. Average speed 85 mph. MPG 21.2 over 70 miles.
So on a long journey, I could if I wanted double my MPG! Only problem is at the lower speeds I was almost bloody falling asleep and without the climate control it was horribly stuffy.
Just goes to show what you can coax out of it though.