Why is my 228,000 miles mpg BETTER now?

Let me set the stage

My 1998 Suburban 2 wd-bought for $2950 195,000 miles in 2007

is our second car

We needed something when "cash flow" ha,ha problems happened in 2006

so Pilot Titan Prism got sold ($39,000) and Prius+ancient suburban($22,850+2950)

got bought-improving family mpg to well above 30-from maybe 19mpg-ongoing fuel savings

and we retained the ability to evacuate 2 leggy greyhounds 4 or 5 crated cats+3 adults.



Anyway I sub teach sometimes/

One school is exactly 10.2 or 10.3 miles away(return leg a bit farther)

I have made the trip there-last year-many times

Last year-in these temps-40 DEGREES am 68 degrees pm

I would STRUGGLE to get to 15mpg on the cold engine trip out .7 gal out

On the trip home I would OCCASIONALLY hit 16 -but usually high 15's

Now I am crossing the Mississippi- probably 250 foot altitude gain loss-

Guessing since I DWL (follow the slowest truck I can find-usually dropping to 40 mph on 50 mph bridge) the bridge is nearly a wash-but doesn't matter since



My QUESTION-

Why am I getting 16.2 16.4 16.1 on my 6 trips-in this weather??

roughly .8 better 6-7% better than usual/.



Now I did just change the oil-but to my usual Mobil 1 10w30

I have never thought that Old oil was more viscous(granted it does feel a bit sticky at times)

I change oil once a year-extended service mobil 1-$31 at WAL mart



Is there ANY CHANCE that the ethanol content in gasoline has been decreased

since oil is now cheaper -much cheaper-that ethanol

Surely the EPA doesn't require a full 10 or 15% ethanol

Yeah my mpg-seems like "pure gas" MPG

Not 10% mpg

What is the GOV actual requirement for ethanol??

Isn't it quite a bit lower-for oxygenation=than 10%-even in cold weather?



Now I guess it is faintly [possible I am doing something different

maybe I am gliding more on the bridge-actually putting it into N

I never switch off the engine-not even for lights(unless it is a 2 minute light-none on this route-and I glide in D because at less than 40 mph the suburban glideS in D as if it was in N-much above 40 mph and you can feel that trans causing engine braking-

under 40 mph and when you lift off it is as if the trans has been disconnected from the driveshaft



So any chance the ethanol percent is down??





Oh at the time-2007-I would have preferred a minivan-honda toyota-

but they were 2x the GM

And in hindsight-the GM has been great-extremely reliable and relatively easy to DIY parts switch-brake booster radiator intake manifold gaskets timing chain and gears(didn't need it)-starter door handles belt tensioner sway bar mount

and many other things that have slipped my mind

If I had to have a shop to the repairs-it would have been maybe $7000 or so

but DIY maybe $1500

and parts for older GM trucks are cheap and available readily EVERYWHERE



And it gives 21 mpg on long trips-not horrible considering it is a 5200 lb brick with a somewhat ancient drivetrain( well developed and reliable obviously)



Secondary question-any 2004-2006 GM 5.3 owners out there??

Do you actually get the 2 mpg city more than the last 5.7's??

Mine is rated 12/17 the 2004 are rated 14/18

they -2004 have much better brakes and much better 14% EPA CITY rating

Tempted to get one-once oil spikes and the HUGE SUVs become pink elephants again

yeah owners will bail about big time at $4/gal-last time that essentially gave them away at about $3.50/gal

and they stupidly switched to mid sized SUVS-to get the same 15%-20% better mpg they could have gotten with mild hyper milling-for $35,000 less



USA-E-INS really won't do basic arithmetic-they panic-sell sell when they should modify driving habits-and drive less-or drive the actual car-more



So

1) Any chance ethanol concentration is lower now that oil is so cheap

2)How does the 2004 2006 5.3 perform -2 mpg city better than last 5.7s?

The newer 5.3 with AFM not on the table-rear doesn't "fold flat" too expensive and AFM MIGHT be responsible for increased oil consumption in some models(engines occasionally actually failing-but usually just sucking in 1 qt per 1000 miles or some such-can't imagine that much on in CC does FE plug fouling-any good)

Charlie

Why is my 228,000 miles mpg BETTER now?