Interesting information in here.
When I use 87 - 89 octane fuel, my milage gets worse.
So I guess my timing on the engine is set for premium.
My owner's manual says that under light load conditions,
I can use 87 octane. (I seldom drive under light load conditions.)
Thus, I use 91 octane or higher. (Page 6-2 of 1995 Owner's Manual.)
As I am usually hauling people & gear around, I have been using
91-92 octane and getting 20-21 mpg on the highway. (3-4 people
and gear in the Blazer.)
I do get a "bad" tank of gasoline, once in awhile (idles with a
"clunka, clunka, clunka, and has poor accceleration). Then I just get
a bottle of gasoline additive in the tank, and drive it out.
The 6.3L has enough 'power' for my needs. I have a trailer, but no
hitch on the Blazer. So have not tried to pull anything, yet.
Have been very satisfied so far, when the Blazer is "healthy".
Need the 4-wheel for Wisconsin winters (and summer potholes).
One of the people I drive for lives on a very remote, township
dirt road. Has been ok in dry weather, but a mess after a large
rainstorm, or any amount of snow. (Last serviced.)
Saw that Shell commercial. And almost got a driving job with them at one time, years ago. NOT a gas truck driver, either.
Most TV ads are 'barely' legal.
Will keep an attentive eye on these forums.
