Getting 8.5 mpg need help

[BlueCollarTahoe]

so for a while i been getting more or less 8 mpg. when i fill the tank it usuallt says around 208 210 estimated miles. last tank i got 218 before i chickened out and filled up. i run all terrains on the factory 17. nothing crazy. i think this is low. i took it to my shop the guy the said the computer was all messed up and reprogrammed it. it worked some i was getting another 1/4 tank more or less. but even for city driving it still feels low. where do i start to figure this out? is this just the truck or is something wrong?

 

[Scottydoggs]

you drive all local stop and go? i dont see over 10 really, all local with hills.

 

[retiredsparky]

Are you calculating? How many gallons for that 218 miles--about 27gallons?

 

[bottomline2000]

8.5 is low. I got a 3k stall converter and I can get 11-12mpg city with 3.42 gears and a 4l80 with its tall 1st gear with 24s.

This ought to fun..what codes are you seeing? Check engine light?

Sent from my SAMSUNG-SM-T377A using Tapatalk

 

[6speedblazer]

i could see 8mpg out of all city driving.

but to dig deeper, any codes? miles on engine? when was the last tune up?

 

[BlueCollarTahoe]

you drive all local stop and go? i dont see over 10 really, all local with hills.

daily i drive about 25 miles give or talk. 15 of those are highway speeds. rest is stop in go city driving.

Are you calculating? How many gallons for that 218 miles--about 27gallons?

26 gallons. been following about 6 tanks on Shell regular. 218 was the farthest ive pushed it. usually i chicked out around 200.

8.5 is low. I got a 3k stall converter and I can get 11-12mpg city with 3.42 gears and a 4l80 with its tall 1st gear with 24s.

This ought to fun..what codes are you seeing? Check engine light?

Sent from my SAMSUNG-SM-T377A using Tapatalk

i was getting an EVAP code (large leak PO455) but i havent seen it in a while. other than that no codes and none pending.

i could see 8mpg out of all city driving.

but to dig deeper, any codes? miles on engine? when was the last tune up?

the car has 108k. i got the tune up done with ac delco stuff when i got the truck close to 2 years ago around 92-93k miles. 2004 Tahoe LT. i have AT nitto tires on the factory 17. a push bar on the fornt that weighs about 50 lbs but i was getting this before the pushbar. where should i look first? a coworker of mine has a same year yukon says his est on tank fill is usually around 290 300.

 

[Doubeleive]

I can probably make mine get that low but I'd be punishing it pretty hard which I used to do but it cost's to much to replace transmissions and rear ends all the time, you might want to check your 02 sensors, cat's, maf, change your air filter, make sure your tires aren't running around @25psi, clean your throttle body, run some injector cleaner thru for a few tanks at least a couple bottle a tank. any of that might help

 

[BlueCollarTahoe]

I have the torque pro app and can get numbers at both idle and under load i just need specifics what to look for if someone can tell me what to watch for if it will give an idea where to start looking. i mean i know its a SUV and city driving kills mpg no matter what but damn if 250 to 300 a tank is really normal i would enjoy that better than the barely 200 i get now.

 

[BlueCollarTahoe]

I can probably make mine get that low but I'd be punishing it pretty hard which I used to do but it cost's to much to replace transmissions and rear ends all the time, you might want to check your 02 sensors, cat's, maf, change your air filter, make sure your tires aren't running around @25psi, clean your throttle body, run some injector cleaner thru for a few tanks at least a couple bottle a tank. any of that might help

long ago i had rich mix codes and changed out the 02 sensors and it went back to normal. on the driver side. air filter is new, MAF and TB i clean every 3 months. ive ran BG cleaner in every other tank. still the same.

 

[swathdiver]

Ok, so you've got a 2004 Tahoe, which motor? 5.3 LM7 or L59 Flex? What rear axle ratio? Exactly what size tire are you running? What was stock size and what air pressure are you running in them?

Most importantly, you said you are running Shell, but what grade? Around where I live, Shell can always be counted on to deliver about the worst fuel economy as possible; even with their 93 octane gasoline.

Does your Torque Pro App show the alcohol content of the fuel?