Got 25 mpg this past week, 98 blazer, 4.3, automatic, stock height and wheels/tires, high flow cone filter, 80% hwy @62mph, 20% city, weighed down by 2 12" subs in a huge rhino lined box and a couple of big amps

 

'98 LS 4dr 4wd 107,000miles totally stock except slightly oversized tires. I average 20 mpg, 17-18 in town, 21-22 on the hwy. My driving style is probably wimpy compared to a lot of people.

 

11.054 gallons pumped , 281 miles driven , comes to 25.420662203... MPG

90% HWY 10% Stop-N-Go , drove from Evansville Indiana to Effingham Illinois to Mt Vernon Illinois back to Evansville Indiana. 4.3L v6 , ran on 2HI. Tires over inflated to 50PSI cold. k&n air filter , performance plugs n wires , high mileage 10w30 oil and generic filter.

Fair weather , was ~60F degrees today , once sun went down dropped to about 38ish

EDIT: '99 Blazer 4x4

 

Man, I'm afraid to even check lol. I have a 2 inch lift and 31 a/t's. They stick out past the fender and I know I'm getting pretty bad gas mileage. How do you guys check your mileage when your gas gauge fluctuates so much? Mine moves too much for me to get an accurate reading.

 

Fill the tank .. reset the Trip Odo .. drive .. divide the trip odo by gallons of fuel purchased

Example: Say you go 200 miles , you return to the fuel pump and pump 10 gallons even , your MPG is 20

 

With dedicated winter tires & crap winter fuel we're getting 15.8 mpg. About 50/50 stop n go/highway. That's carbed with HEI ignition too (on a '00 Vortec). Can't complain at all.

Wife drives it 99% of the time, but I drove it for the first time in months last Saturday. Wow what a difference from the old motor. Nobody got the jump on me at any traffic light. At least 100hp more - the old motor was pretty worn. Lots of fun! Much more enjoyable to drive now. Just light pressure on the pedal sets you back in the seat. Love it!
Her last highway trip she got around 18.

 

I've been getting a fairly steady 15, winter or summer. When I first got it I wasn't aware of the gas gauge problem and was convinced someone was stealing gas from me, and since I was used to 30+ from my old car it seemed likely. Now I think it's a combination of my driving, the fact that I rarely drive it more than 10 miles at a time (and in the city at that), and 160k miles on the engine.
Still would like to see 20mpg out of it someday, but not bad enough to slow down
Maybe I'll drive to Cheyenne and back, just to get it on the highway for a while

 

18-19 MPG per the 80% highway driving on the last tank. Stock everything but with new 235/75R15 Wrangler RT/S on all 4. A new fuel pump, fuel filter, evaporative vent valve and purge solenoid also helped increase mileage.

 

2004 stock blazer, 4wd, 4.3L V6 automatic. Even driving in 2wd, being careful to not even let the rpm go over 2000 and with pretty much clear roads I get 12.5 mpg. Technically city driving, but never stop and go - 50 to 85 km/hr.

 

We get between 15-16 mpg with a carbureted '00 Vortec with snow tires, winter blend fuel with about 15% ethanol in it .... so I'd say you've got some issues to look into.

Air filter for starters. Upstream o2 sensors next.