Poor Gas Mileage...

Change tires recently?

 

OK ill give em both a check, I think my cat could be going bad soon tho

 

I bought mine brand new, saw it unloaded off the truck. 16 is about right since day one.

When I put BFG KM2 33's and FJ 17" trail ed. Wheels on it, I now get 13ish in the city, but on highway if I start slow, keep it at 2000 RPM's I can cruise at 70-75 for long steady distances and get up to 23 MPG!!!!

I know it makes no sense, but it's true!

FYI I use GPS speedometer, not dash speedometer

 

I have a 05 double cab 4x4 auto and have a 4 in lift and 285/17 tires and no matter town or hiway i get around 9-10 mpg, i drive around 55-60 all the time. I usually drive in 4th instead pf drive because it pulls easier and dont want to downshift all the time. Iv tried it both gears and its worse in drive. When i first got it ,it had 32 in tires on it but no lift and was getting around 17 mpg? Really all that changed is lift. I cant afford to drive it anywhere. I want to take it to the mountains here in colo to drive sum trails but im 4 hrs from mountains and it would cost me bout 80 bucks in gas just to get there

 

Have you cleaned the MAP sensor?

 

I havnt tried that. Ill give it a try. Thank u

 

Have you checked for build-up behind the throttle valve?

Have you checked the ends of your vacuum hoses for splits and cracks?

How many miles does it have, and is it on the OEM fuel pump/fuel filter?

 

I have checked for vac leaks and that, fuel pump is orig it has 136,000 mi.

 

I'm with the "lucked out winter mpg suck truck" segment of society. I had both a 1st gen and 2nd gen V6's, and driven 30 to 40 miles one way to work for 20+ years in both PA and VT. Both drives also were about 2/3 highway and 1/3 normal roads. I always lost 10 to 15% during winter on both vehicles. Nothing else affected that for me.

Current 3rd gen is noticable / same, I just don't drive to work anymore so not as many miles to notice. Also, just another point of ref (so you don't have to try) - I used a mix of eth and non-eth gas throughout the years, no difference. Now I just use non-eth as the tank doesn't usually get emptied in one month.

 

There's a Zombie Post!
Re-calibrated the Speedo / Odo?



At 50 you are going 5.4 MPH faster than your truck is registering.
That means you are going 10.8% faster and 10.8% further so if you are not logging that mileage you are getting 10.8% worse perceived fuel economy.

Right away that explains 17MPG down to 15.
Your tires are likely larger than your gearing can handle thus the need to drive in 4th all the time and never into fuel sipping Over Drive. Time to regear that pumpkin.

 

Cripes F me... haha. I don't notice these things.

OP join Feb 2011, OP is Feb 2011, last seen Dec 2011

 

LOL - No worries! We have all done it.

 

Clean throttle body, clean maf, change engine air filter, change oil, REPLACE PCV (this netted me 1.5 mpg at least), run two bottle of Techron complete fuel system cleaner in back to back tanks, one per tank and do this as well for the fudge of it.

And OP has been gone since 2011, just noticed this

https://m.youtube.com/watch?v=x2YNC_CMbC0&pp=ygUWVGFjb21haG9saWMgcm91Z2ggaWRsZQ==