gas milage

[2004tahoe]

i have new plugs, 115k on the truck ...all fluids changed

i get less than 260 miles on high way....i dont even wanna mention city numbers...

the highway milage is with cruise control doing 70 mph



what do you guys think i can do

 

[07Burb]

Do you have a clean air filter in it and have it properly tuned up??

 

[2004tahoe]

k&n on the filter....its new....


i was thinking Pcv valve and oxygen sensors ...but i dont waan replace all 4....


do the rear have anything to do with fuel economy or are they just to check the cats?

i get better gas milage in my 2500hd diesel duramax.... same size tank if i'm correct

 

[smurphy80]

Im having the exact same issues, long time fuel curves are perfect, clean filters, light driving, new plugs, new o2 sensors, etc. The only thing I can come to is that its due the cold weather during winter. City mileage I'm around maybe 200 miles to a tank if im lucky. This summer, my mileage was no where near that low.

 

[M3PO]

I just bought my 06 Denali this winter, and the MPG has been terrible, about 10.5 city/12-13 highway. I know it is a 6.0 is not my little 1.5 Mazda, but the motor takes forever to warm up, so I am guessing that has a lot to do with it. I drive like grandpa and I only start the truck and let it warm for about 30 seconds to 1.5 minutes.
My friend is a long time dealer tech, we are going to go through the whole truck and make sure everything is to the letter. I am hoping maybe a new thermostat will help, but I doubt it, as when it gets to temp it holds just fine.
It has warmed up here in the midwest, and it seems like the mileage on the current tank is going to be considerably more.

Not tyring to thread jack, just my observation.

 

[Gordy]

Pre cat o2 sensors are the ones to check. fuel injectors LTFT STFT should be +/- 10% ideal 0.

This seems to come up a lot here mine sucks to. Anyone ever think its the gas all the way around no matter where you go. Think about it. Even my 2009 acadia gets ****** milage this winter its a 6 banger 11 in town yeah the remote start kills it but...... We are paying 3 plus dollars a gallon for gas that has extenders in it. ethanol being one of them

 

[Goose]

i just bought my 2002 Z71 85,*** in Nov. with running it 10-15 min in the morrning to warm up, and 17 miles to work hwy. worst was 8mpg best 13mpg. im in minnesota, so its cold and i have to go through snow every couple of days. and buying it in the winter doesnt help much, since its cold out and i cant just pop the hood up and hang out in the driveway all afternoon going over my new truck.