Had an epiphany this evening...

Some vehicles are fairly insensitive -- mpg-wise -- to driving technique. Others respond with wide variations. So what makes the difference?

Once upon a time, I drove a '75 Toyota Landcruiser that I've always remarked to friends got 14 mpg, didn't matter if I was pulling a trailer up hill or coasting down it in neutral. 14 mpg, clockwork. ('Course, gas cost about 50-75c a gallon then.)

Years later (the last eight months) I'm driving the wif's hand-me-down conventional Ford Explorer. I always figured I'd be able to bump up the mileage she was getting with it by being more 'thoughtful'. She'd do things like run it with the A/C on max and the windows wide open; drove me nuts. I'd watch the traffic lights blocks ahead and coast or drive towards 'em to hit the greens. I started driving it full-time last Sept, handing my '92 Exploder down to the kid. I haven't worked the calculations yet, but my gut-feel is that I haven't been able to bump the mileage up noticeably from what she was getting, about 16 mpg.

Fast forward to this week when she's out of town and I'm driving her new RXh. (Hoo Boy!) Check the fuel data I've been plugging into the DB -- we're third from the bottom at 21.1 mpg over the first 5k miles. She gassed it up a day or two before she left, so I've been driving it since Monday and have run this tank up to 29.2 mpg over ~100 miles, as reported on the on-board screens. (Note, the 21.1 figure is from gas receipts and manual calcs, and witness the discussions on differences betwixt.) That figure would get us up to a few positions from the top of the RXh FE numbers in the database.

I'll admit:
o she drove it through the cold season. (As cold as it gets in the Willamette valley, OR) Note threads re: lower mpg in cold months, due to extended ICE warm-up time
o through the engine 'break in' period
and I've been:
o running 75/25 city/hwy,
o in good weather,
o taking advantage of what I've read here, WRT stretching mileage, but haven't gone to extraordinary means.
o I have started running the engine to accelerate from stops vs. trying to do it with battery power, saving that for the long, level stretches once at speed.

So, I'm left with the question, what characteristics make a car respond to 'gentle' technique...or not. What have I missed, re: bumping up the mileage in the '00 Explorer? I've never gone out of my way to try to get lousy mileage with the Explorer, but from average to 'really trying' I can't get it to budge.

Benton 21may08

 

Yes, they are very sensitive to driving conditions and techniques.

Here is my best tank:

My worst tank is 19 mpg. That was driving during the middle of the night during winter. The temps were well below freezing, it was very windy, and I was going over 80 mph.