Need advice on how to get better MPG.

[2004YukonXLDenali]

So Far I did the plugs with the Pulsar Pulse spark plugs and also I did the 8.5 MM plug wires, also installed a cold K&N air filter. Im still trying to find the fuel filter to change that out. Is there anything else Im missing?

 

[Max]

Fuel filter is above the frame from the driver's door. Electric fans, tune, and longtube headers/exhaust make a huge difference in mileage on these trucks. Swapping the differential fluids to royal purple or amsoil make a good difference as well since these trucks are full time awd.

 

[Thumper8302]

So Far I did the plugs with the Pulsar Pulse spark plugs and also I did the 8.5 MM plug wires, also installed a cold K&N air filter. Im still trying to find the fuel filter to change that out. Is there anything else Im missing?

how are u likin those plugs.. ive heard if them but havent heard much lol

 

[rich5368]

A tune is going to give you more than anything else. It is a v8 so 18-19 on the hwy is going to be very good mpg for your truck. I've got a stock 03 and I'm getting 14 city 18 hwy and I'm pretty happy with that.

 

[Repo503]

I wouldn't even worry about mileage. Does anyone here really care about mileage?

 

[Z15]

There is not much you can do to increase mileage in a Yukon Denali XL. You are pushing nearly 3 tons of metal down the road and its takes fuel to do that. All the gimmicks and performance parts just cost you more money and will never give you a return on your $$ spent. You will get lots of comments from users that they changed to a K&N and the mileage with up 2 mpg. That's impossible unless the filter they replaced was loaded with dirt. Most making those claims have no way of substantiating that claim. Think about it for a moment, if mpg increases were that easy the car company's would be installing these things as standard equipment because they are spending millions trying to gain 0.10 mpg.

It is worth it to spend several hundred $$ on a tune to gain 1 mpg (if that)? Will any of these tuners guarantee they will increase MPG? I doubt it because there is no way to know how the person drives.

Few things you can do. Drive moderately. Its been said the difference between 55mph and 70 is 20% more fuel burned. Don't haul around anything you do not need to, extra weight burns more fuel. Keep tires properly inflated, don't change sizes from stock, bigger, wider and aggressive tires cause more resistance and drag and add more weight to the vehicle, make sure alignment is correct. Don't let the vehicle idle or warm up, it only wastes fuel.

If you want good mileage, buy a Malibu or a Cobalt.

Fuel filters are located in the tank after 2003 and are do not need to be serviced.

I've got a stock 03 and I'm getting 14 city 18 hwy and I'm pretty happy with that.

I had a 2004 and that's exactly what I got with the vehicle completely stock!

 

[rich5368]

I did get a good deal on the superchips for my 04 yukon shorty and driving the same as I did before I did see a 1-1.5 mpg increase on the highway. My in town mileage however went down about .5mpg so it's a tradeoff. Is it going to change a lot with mods no. Will your truck sound manly with an exhaust and have more throttle response with a tune and such? Sure.

 

[MOBmentality]

i have heard using cruise control makes a huge difference because you make thousands of micro corrections while driving that the truck feels as acceleration.. even if you have already let your foot come back the 1/16 of an inch you were pushing it.. before YOU even noticed the acceleration occuring..

also .. i read a super cool article about how on MOST vehicles for a 20c difference that running premium was actually cheaper than running regular.. NOT even acounting from possible maintenance savings..
it showed that if you put in 15 gallons of regular at $2.75
it equals $41.25
where 15 gallons of premium was 2.95 is $44.25

If running premium got you an extra 1-2 miles per gallon then at 15mpg you would see an extra 15-30 miles on a tank.. which is relevant to an extra gallon or two of gas..

SO where it looks like you saved $3.00 at fill up.. you lost a relative fuel capacity of 2 gallons.. so at $2.95 a gallon.. the extra 2 gallons of mileage you got actually SAVES you $2.85 cents per fill up...

and the heavier your vehicle and more aggressively you drive.. will hurt mileage over all.. but will make this solution more true.

And.. if assuming running premium actually does save on maintenance costs and has less shit in it that harms MPG in the long run AND is more likely to cause repairs earlier.. then premium SMOKES regular in the economy range.

 

[General Stalin]

I know people like to save money, but I do always chuckle a little bit when people on here make a post about saving mileage.

A Yukon Denali XL? That's like a 6,500 lbs. truck with a 6.0L 364 c.i. with full time all-wheel-drive with a boat load of bells and whittles. It's American Excess at it's finest. I'm definitely not saying there is anything wrong with it, I own a 2003 Denali myself (not the XL.. a little too long for me) and I love it more than anything, but the fact of the matter is that fuel economy should be the last thing on your mind when riding one of these pricey boats. You want power. size, and towing capacity, then you need to use some gas, the only way around it would be to be a later model with a hybrid engine that gets like 24 MPG highway.

My Denali has pretty much everything I could possibly want in a vehicle and more, and it gets between 14 and 18 mpg average and I am totally comfortable with that. The price at the pump is a price I'm willing to pay for something so pleasurable to ride in.

 

[Z15]

And.. if assuming running premium actually does save on maintenance costs and has less shit in it that harms MPG in the long run AND is more likely to cause repairs earlier.. then premium SMOKES regular in the economy range.

Running premium in a engine not designed to run premium will not help a bit.

Using high-octane gas in a car designed for regular accomplishes little except more rapid combustion of your money. Some refuse to believe this, claiming, for example, that premium gives the family Toyota better mileage or more power. These people are in dreamland. Others say premium is purer or contains detergents that will cleanse your engine of uncouth deposits. Likewise misguided thinking--government regulations require detergents in all grades of gasoline. (BP Amoco, I notice, asserts that its premium gasoline contains more detergents than legally required; if you think that's worth 20 extra cents a gallon, be my guest.) Some automotive types claim that using premium in a car designed for regular will make the engine dirtier--something about deposits on the back side of the intake valves. I've also heard that slower-burning high-octane gas produces less power when used in ordinary cars. Believe what you like; the point is, don't assume "premium" means "better."

 

[General Stalin]

People make up waaayyy too many myths about high octane fuel. High octane means one thing and one thing ONLY:

High octane fuel is just gas that better withstands pre-ignition. Performance engines have advanced timing and high compression ratios than normal engines. Because of this, normal octane gas (or 87) would actually ignite too early because the high performance engine compresses it too much. This causes knocking/pinging and all that fun stuff. High octane gas has compounds in it that resist ignition, so it can be compressed more before igniting.

That's it.

 

[cam3439]

Yes this is true, but if you have ANY pre-ignition/detonation before the piston is all the way up then you have WORK AGAINST the engine and thus less fuel economy. A higher octane will lessen, if not eliminate, the pre-ignition/detonation that happens before the piston's full compression stroke. BEFORE the BB tune my truck ran more efficient at 89 than at 87, so that's what I used. The engine's idle smoothed out quite a bit and I noticed more miles per tank than with 87. I haven't tested the mpg's since my 93 BB tune, but we'll see what happens.

 

[General Stalin]

Well, these engines in our trucks were all engineered and designed to run efficiently on 87 octane fuel. They are not high compression engines, and the reason why BB tune requires the use of higher octane fuel is because he advances the ignition timing so the spark comes just a LITTLE bit later to compress the fuel/air just a LITTLE bit more to get a tad more power out of the power stroke.

 

[WoldD90]

Other than driving responsibly, keeping your tires inflated properly and keeping your speed down, there is not much you else you can do.

The e-fans did not do much for me on my 6.0, but they did on my LR Defender. The K&N helps the breathing a bit, but I have not noticed any huge gains.

 

[Fyrcaptain]

Absolute best hiway I have ever gotten was 19.8....I say 20 cause it makes me feel good. That's using regular gas, resetting the mileage computer right as I get on the hiway, a/c on, fully loaded, 38psi in the tires.
I drive it 95% hiway but my 5% round town is in the 14's.

It's a battleship, I don't give a shit what the fuel mileage is, I didn't buy it for that as my daily driver beater gets 27 city. Even if gas goes to $7, I'll still keep it cause it ain't my daily ride.

 

[Eagle]

narrower tires, lighter wheels.
I picked up about 1-2 mpg CITY when I switched down to 20s, I bet I'd pick up another 1 on 17s.
I get a little better MPG on 88 vs 86. I run about 1/2 a tank and then alternately fill up with 86 or 92 at Sams... their premium is the same price as 86 elsewhere so it isn;t costing me anything extra to run premium or a mix.

Honestly it feels a little dead on 86, I think it is pinging slightly and going to a very conservative "poor fuel" map. I'm already 10% down on power at 3500 ft. ASL.

 

[gtbigup01]

It seems like it doesn't matter what people drive they always ask what to do to get better gas mileage. I traded in an 04 Infiniti G35 to get this truck and i got 18 MPG agressive city driving on tthat car (rated 20/27) and was pissed I didn't get 20MPG, now driving like miss daisy I get 15MPG on my truck. Man do I miss my G35. Well not for the gas mileage, just that this is my first automatic I ever owned, I went test driving sticks last week just for the fun factor Mazdaspeed3, VW GTI, Subbie WRX, oh man!!!!!!!!

 

[JoeOmerta]

Things to ask yourself...

Is your mileage above 80,000?

If so,
When was the last time you replaced your:
o2 sensors?
spark plugs?
spark plug wires?
air filter?
gear oils?

Changing all of those can potentially help your fuel economy. I say potentially b/c every vehicle is different and results may vary.

What are your driving habits?
Heavy foot, light foot, do you let the car warm up before driving anywhere?
(by warmed up, i mean the car switching to closed loop)

What size rims do you have?
A smaller rim size is easier to turn compared to a larger wheel.

What pressure do you keep your tires at?
For ideal ride conditions and overall longevity of the tires, 34psi is recommended. On long highway trips it can be pushed to 40psi+ but be wary of load ratings and what the tire is capable of handling.

When was the last time you cleaned your MAF and throttle body?


I would say for a once over great tune-up(if these things haven't been taken care of already)...
1) Put a bottle or 2 of sea foam in a full tank of gas and run it down to 1/4 tank or so.
2) Clean the MAF with an electrical component safe cleaning solution(i use crc)
3) clean throttle body with throttle body cleaner(i use an old tooth brush to scrub it)
4) Run a can of sea foam in the intake system
5) change oil
6) change spark plugs + wires
7) change all 3 gear box fluids
8) change trans fluid/filter
9) make sure tires are properly inflated
10) change forward o2 sensors

If you have a vehicle with 80,000+ miles on it and those things haven't been done, you will notice a nice difference in mpg and performance

 

[blrmkrl83]

2005 Denali XL. 9.6 MPG at 100MPH. How's that. Speed does make a HUGE difference. I get 18 MPG at 70 and about 14.5 at 85.