Fuel Economy Dropping

[Scotto2323]

Never got the best fuel economy on my 2008 LT, but it seems to be getting worse. I started out getting may 13 mpg when I first bought it and now its down to 11 mpg. I thought I would have seen an increase after just doing plugs, wires, clean K&N Filter, and some new Mobil 1 but hasn't seemed to help at all.

Any other suggestions, I have 93k on it now. Plus I imagine its gonna get even worse with the 20's and 295/55s I'm about to install.

 

[Sarge]

Im getting 15 city 19 highway

Try cleaning the tb, seafoam is wonderful. After all that check tire psi and i would unhook battery for a bit and let it relearn everything.

Try a tank of 93 also

 

[Ridechevy09]

Damn, I get 16 with 35 12.50s

They're so many factors that can play a part in this.

Filters, plugs, wires, tires. And many more. I would get it serviced. You could try installing a catch can as well.

Sent from my SM-S978L using Tapatalk

 

[iLikeEggs]

Try cleaning your mass air flow sensor. It's on top of the air intake tube coming off the air box. Buy a can of MAF spray cleaner at your favorite auto parts store and just spray the heck out of it. You will need a star key to get it out, also available at the auto parts store. Only two easy screws. Takes about five minutes from start to finish but you will probably notice a difference, especially if you have a lot of miles on the beast. Cheers.

 

[mr tahoe]

Im having the same exact problem and im going crazy cleaned the throttle new air filter spark plugs, i did every thing and it seems that its getting worse not better

 

[Erik G]

I would go for a nice long freeway drive at 65 and see what you are getting. I just did one, and averaged 20.4 MPG over 200 miles from Austin to Houston at about 75 mph. Around town I'm getting like 10mpg

Stop and go will kill your mileage like nothing else. If you just started using your AC for the spring, that makes it worse. I played with it during that 200 mile trip

 

[mr tahoe]

Im staritng to feel that the maf is the problem ill try cleaning it today will post results

 

[mr tahoe]

I just cleaned the maf an ooohhh boy what a difference!!, took it on the highway and the engine feels stronger more responsive

 

[ccapehartusarmyINF.(ret)]

also i noticed to calculate accurate fuel economy i had to run my gas tank dry bucause the fuel light would go on at like 360 to 370 miles but it would keep going to almost 440 miles before it ran dry wich was a difference of almost 3 gallons
cuz when the fuel light just goes on it barely takes 29 gallones to fill it when the tank is dry it takes over 32 gallons

 

[iLikeEggs]

Are you referring to the standard 26 gallon Tahoe/Yukon fuel tank? You can get 32 gallons out of it? If so that's pretty comforting to know. What vehicle do you have?