bad gas mileage

[preciouscargo]

I have a 2000
GMC Yukon xl. I noticed I'm getting 10 mpg around town. It has 135,000 miles . I'm not a lead foot I drive like a grandma. When I walk by the fuel tank there is a fair amount of gas I can smell. I have never seen a puddle of anything under the truck.

 

[Vette66]

I get 10 mpg in town and now on the freeway. Not sure what I have going on. I don't have a gas smell. I started getting bad freeway after a tune up. Wire, plugs (yes I went with OEM recommended), MAF clean and TB clean with approved cleaner. Good luck the common answer here is "Welcome to having a big ass truck". A few MPG make a big difference. I am hoping I can figure it out with my new AutoCal from Black Bear Performance. I will post once I figure it out on my end.

 

[OHSIXX]

Plugs, wires, clean MAF & throttle body.......when were those done last?

I believe you have an external fuel filter on that year if I am not mistaking-if it is-should be on driver's side rail-change that too.

I have a 'shorty' Yukon with a 6.0 and I get 16ish in the city and 22ish on the highway---but I have a tune

 

[JochenWoern]

Plugs, wires, clean MAF & throttle body.......when were those done last?

I believe you have an external fuel filter on that year if I am not mistaking-if it is-should be on driver's side rail-change that too.

I have a 'shorty' Yukon with a 6.0 and I get 16ish in the city and 22ish on the highway---but I have a tune

So what did you get BEFORE your tune?


I have never made it above 11.5ish in the city EVER. Do not go on the freeway too often, but would imagine to get around 15 at the most unless it would be a long cruise.

 

[YukonXLPerk]

Plugs, wires, clean MAF & throttle body.......when were those done last?

I believe you have an external fuel filter on that year if I am not mistaking-if it is-should be on driver's side rail-change that too.

I have a 'shorty' Yukon with a 6.0 and I get 16ish in the city and 22ish on the highway---but I have a tune

Alright, alright.....enough bragging! What tune? I want I want

 

[Vette66]

No doubt those numbers would be amazing.

 

[OHSIXX]

So what did you get BEFORE your tune?


I have never made it above 11.5ish in the city EVER. Do not go on the freeway too often, but would imagine to get around 15 at the most unless it would be a long cruise.

From what I remember-around 14 in the city and 19ish on the highway.

Alright, alright.....enough bragging! What tune? I want I want

Blackbear in-person tune FTW!!

No doubt those numbers would be amazing.

Just lucky I guess lol...... I see my best fuel mileage when I get non-ethanol gas. I have a premium gas tune as well so I pay for it at the pump but get better mileage-its basically a wash in the end I think. Next time a make a run up north or back I'll snap a pic of the D.I.C. for proof


Here is shot of my way back from getting my in person tune-about 100 miles one way......I was also a little heavy on the skinny pedal(demo'ing the new tune) and doing 75-80 on the freeway.....

 

[zieglerj-pdm-specialist]

From what I remember-around 14 in the city and 19ish on the highway.



Blackbear in-person tune FTW!!



Just lucky I guess lol...... I see my best fuel mileage when I get non-ethanol gas. I have a premium gas tune as well so I pay for it at the pump but get better mileage-its basically a wash in the end I think. Next time a make a run up north or back I'll snap a pic of the D.I.C. for proof


Here is shot of my way back from getting my in person tune-about 100 miles one way......I was also a little heavy on the skinny pedal(demo'ing the new tune) and doing 75-80 on the freeway.....

I agree stay clear from the ethanol no matter the octane rating put in the gas that has zero ethanol plus a tune might help also. Change the plugs, wires, EVG valve, fuel filter, and get a new air filter. Plus if you put on a cold air K&N filter on it so it gets more clean air. With the K&N I like to keep my engine bay very clean so my filter sucks in clean air. Just a suggestion. Plus I wouldn't trust a picture od average Miles because he could have hit reset and been coasting or just driving in town and not accelerating.

 

[OHSIXX]

Plus I wouldn't trust a picture od average Miles because he could have hit reset and been coasting or just driving in town and not accelerating.

Don't hate and wouldn't lie to my TYF family...........and I just got back from upnorth with a 19.8 MPG to boot........a did a lot of coasting...duh

 

[JochenWoern]

Don't hate and wouldn't lie to my TYF family...........and I just got back from upnorth with a 19.8 MPG to boot........a did a lot of coasting...duh

Glad you set the record straight here Jason, I was wondering why he would suggest such thing?

AWESOME mileage, that is very cool.