Awl--
Apropo of the very good and kind responses, I figgered I'd address all here.
I guess in a nutshell, I'm saying:
If the ability to downshift is a given (shift lever), shouldn't it be just as easy to force an upshift?? At least in principle? I'm willing, grudgingly, to spend the cupla hundred bucks on the workshop/svc manual, IF it would help me resolve this--either yea or nay.
Would appreciate any other tips on sleuthing this down *definitively*. If the consensus is that I'm playing w/ fire, then I can indeed find another automotive cause! Mebbe just pimp out my ride, or sumpn.... But if I have a better-than-even shot of doing this w/o causing damage, I'll pay to play.
Regarding other points made:
If my right foot gets any "lighter", it will float!! The Scangauge I use has been quite revealing, verifying most of the driving habit stuff mentioned re mpg's. When I lend my truck out for short jaunts (yeah, I'm real popular now!), the apparent diff. between what I use and my neighbor uses gas-wise is astounding. Esp. in a 4500 lb truck w/ a crappy engine. Light-footedness is essential.
The thing that surprised me, and may surprise some here, is the drastic difference a gear makes, on level ground or up hill: an *instant* 3 mpg, and more, by upshifting.
More importantly, when "caught" at about the 40 mph range, the tranny is not willing to shift into top gear, when it easily could, imo, w/o lugging the engine at all. Ergo, my specific mention of "slow highway/fast city" driving.
I was not aware, however, of the transmission wear&tear from lugging. And indeed, one transmission does buy a lot of gas!
A geartronic/tiptronic device was mentioned. Any way to add this?
Tire inflation is important as well, mpg-wise. It's hard to do comparisons w/ an mpg meter, w/o test track conditions, but on a tank-by-tank basis, you can really see it--easy 10%
Another thing you may find pretty wild is that when my alternator went on a
1990 Mazda 929S, my mpg's jumped up *at least* 10-15%, whilst I was on battery alone. Boy, is this giving me ideas!
Regarding the comment on engines/trannies tuned for max mpg's, boy, I think Nissan went out for *spite* on this one, and tuned for the *minimum*! I really can't think of a reasonable excuse for 15-18 mpgs (highway) in a
2004 vehicle w/ a 3.3 L engine (180 hp), even on a heavy truck, w/ a helium-footed driver on over-inflated tires. But it is what it is.
TIA!
---------------------------- Mr. P.V.'d formerly Droll Troll