Old Lurker has a question.
 

One of the most interesting forums on the I-net, I have read posts for years. I finally have gotten up the courage to ask a question:

I (we) own a 2011 Buick Enclave with about 47K miles on it now. We live in SE Florida where it is hot for about 7 or 8 months and nice the rest of the time. The Enclave is used mostly for errands, occasionally hauling a load of furniture or people 20 or 30 miles. Probably 90% of the time is contains only me (skinny ol'phart) and 50 lbs. of bowling equipment. 19" wheels, fairly new rubber kept at recommended pressures.

The mileage stinks, 13 -14 mpg around town and maybe 18 -19 mpg on the occasional trip. We live in an urban area so there is alot of driving where the traffic goes around 35 -40 mph (more or less!) with stops every few blocks or half mile,, etc. so it is not as bad as true city driving.

Personally, I think the shift points are set way too high, the transmission needs a tow/haul mode and a highway mode with lower shift points.

However, the Buick folks say the shift points cannot be changed and have no suggestions as to how I might improve the mileage.

Your suggestions are appreciated. Please do not tell me to simply drive slower etc. I already know that!

Dicnic

Is that a 6-speed automatic transmission that you can 'manually' force gear changes to occur via shift-control buttons or movement (like 2011 Cruze)?

Yes, 6 Speed but .....
 

Using the manual shifting mode only lets me hold it in a lower gear for a longer period of time, NOT force an upshift earlier. Unfortunately the manual shifting mode name is not quite true, as usual.

Go higher on the pressures and try a little pulse and glide to play shifting games?

Maybe there's a performance oriented GM forum that can offer tips on forcing torque converter lockup, too. You'd have to find out what kind of transmission you have and what else it's used in, but there'd be a start.

And no, I don't actually have any idea what I'm talking about here.

It's nearly 5000lbs and has ginormous 19" wheels. It's going to take a lot of energy to repeatedly accelerate and decelerate all that mass.

None of the information you provided matter....(kinda)
1. by a scangauge
2. find a flat section of highway close to you
3. using scangauge, run up 6 miles, reset, run back.
4. do this for 50mph, 60 mph, 70 mph.
your looking for the sweet spot in the rpm curve.
On my Infiniti Q45 it was around 1780 rpms

Second, how much freeway driving total miles a yr, do you do?

Highway driving
 

I might put on a few hundred miles on the freeway per year. Only drive freeways when going north or south for 10 or 20 miles or so. Traffic on I-95 is so bad it is not only dangerous but often not faster than other routes.

Some pretty easy stuff to do without getting too carried away:
- index and gap your spark plugs
- go with low rolling resistance tires like the Nokian Hakka's (check youtube for their rolling resistance test with a Prius)
- go with Amsoil low viscosity ATF
- try Amsoil 5W30 Signature Series or ENEOS 5W30 engine oil
- use a good oil filter like Amsoil EAO or Mobil1 Extended Performance
- if you have a rear diff, put in Castrol Syngear 75w90 since it's the lowest viscosity GL5 and same in the transfer case
- try NMF (gonmf dot com) in the engine, trans, diff, coolant, power steering, and fuel
- try ws2 from lowerfriction dot com in the engine and diff
- don't run ethanol blended fuel
- try to scoop a set of lighter wheels - stock cast wheels are crazy heavy
- led headlights from aliexpress if you do lots of driving @ night/winter

Along the way you can start to learn better driving techniques - in particular anticipating traffic patterns ahead of you.

Good luck!

There you have it.
Not at an efficient speed to gain much mpg.
Back to the comment above.
A lot of stop and go getting that 5k beast moving.

Province of Quebec up in Canada put this out for driving techniques:

http://www.ecomobile.gouv.qc.ca/en/e...lite/index.php

Ecomobile - Ecodriving