Guys, I'm about to give up in my quest to get better MPGs. It seems that everything I do to try to improve mileage actually backfires and I get worse mileage.

Yes, I know these trucks are not Prius'


I cleaned the TB & MAF and reset the ECU and with 90% highway driving I got my best tank averaging out to 14.6 MPG....BUT THIS IS HIGHWAY MILEAGE!!!

I just added a Maggie SIDO thinking I'd get a little more....I just dropped .6MPGs!!!!!!!!!!!!!!!!!!!!!!!!!!!

I try to "hyper-mile" for those that are familiar with the term. I am always looking 4-5 cars ahead and keep my foot of the gas the most I possible can.

I made sure my tires are properly inflated. I'm running 265-70R17 BFG ATs at 39 PSI.

I use cruise and set it at 70 MPH when I'm on the interstate---pulling about 1950-2000 RPMS.

I don't know what else to do. The previous owner told me the plugs were done at the beginning of last year...so they shouldn't have that many miles on them.
I haven't done the PCV valve yet as I'm still looking for a Motorcraft one, not some crappy Fram.----but doubt this will help any

Again, I LOVE MY TRUCK!!! I just don't understand why its getting as crappy gas mileage as it is on the HIGHWAY!! I can understand the city, and know its not a fuel efficeint as GMs...but come on! 13.9 MPGs after an exhaust---and no I didn't "play" once I got it. I have been VERY disciplined!

Would going form Motorcraft Syn-blend to a 100% synthetic oil like Pennzoil Platinum or Mobil 1 help any at all?? .5 MPGs??

I'm just tired of sinking money on things I think will help and they don't.---DirtySCREW

 

Dude that stinks... atleast she sounds great

Try 65 on the highway and see what happens. Some trucks just don't get good mpg's... they are all different. BTW... are you considering custom tunes/tuner?

 

did the previous owner ever change gears?

 

Them the stock size tires? If they are bigger then stock it will slow the speedo giving you false gas mileage calculations. Check the door tag. I bet there big. your probabley gettin closer to 16 in reality.

 

I don't know if theres an o'reillys where you're at but i've seen motorcraft PCVs there

maybe front O2 sensors? but those are a little expensive to just throw at it.

 

Wooooooooh.... did you say not as fuel efficient as GM's? The Silverado was just named one of the top 10 worst vehicles in fuel economy. Watch your tongue!

Using your cruise control can actually end up costing you some petro. Your truck will keep constant speed so if you go up an incline, the speedo increases throttle to keep the speed you set. Cruise control helps if your A.D.D. and can't keep a constant speed with your foot, but otherwise can actually hurt your fuel efficiency.

I believe those tires are the stock size (they were on my '03 SCrew). Your numbers really aren't that bad, but could be better. I can get between 16 & 17MPG and I run 35" tires and almost 6" of lift. I get about 15 overall.

You might want to consider changing the plugs & COP's. I went to NGK iridiums and noticed a difference from the Motorcrafts, which were (supposedly) 3 months old and less than 5k miles. They looked like crap when I took them out. Last time I have a shop do that work.

Could be worse!

 

I think you gave up the right for good gas mileage a long time ago when you decided to purchase a truck...

 

39psi seems a little low

 

kick that TB spacer off...
had a 08 screw for a few months and it adv 15mpg... which i drove it pretty hard and it was bone stock

 

Tires ARE stock size. I dunno if the AT tread is hurting me that bad or not. 39 PSI low?? I normally only run about 36psi. What PSI do you recommend for this size tire (26570R17)

If anyone can send me stock TB bolts, the spacer is GONE!! The only reason I put it back on when I cleaned the TB was because I didn't have regualr length bolts; otherwise I would have kept it off then.

I understand the Cruise situation. Cruise CAN help and it CAN hurt....depends on your terrain etc etc etc. I'm in NC and its flat where I am. Cruise actually helps here.

As far as I know the previous owner DID NOT change gears. I have a rear diff leak and am going to change the fluid with synthetic and fix it then. I'm just debating on whether I should go ahead and replace the axle seals at the same time and do some preventative maintence as I do have 137K on her. I'd hate to spend $$$ on nice synthetc gear oil and have to change it again because an axle seal blows a couple months after I had fix my rear diff. What do ya'll think??

65MPH aint gonna do that much in my opinion. Reason being is I'd only be dropping 100RPMs if that. I don't see how 100 RPMs would make a drastic increase.

And I do need to get a new Air filter...I guess from S&B since I have the Air Force 1 CAI. I doubt that would get to where I want or not.


Yes---I DO want to get a Gryphon...after I get everything done that I want to do "maintence wise". And I wanted to get electric fans. Once I got the electric fans I was gonna try and get a Gryphon. Now electric fans SHOULD definitely help out the efficency of the engine and yield better MPGs.

But I still have to get headers (peferably LTs) to fix my manifold leak. And maybe hi-flow Maggie cats. And synthetic fluids through out (diffs, Trans, transfer case). Then the E fans and gryphon. I figured I see the most performance this way.

I need to win a freakin scratch off ticket!!!!!!!!!!!

Any more help is GREATLY appreciated.

I also urge members here to sign up on www.Fuelly.com You track your mileage and its nice (or not so nice depending on how you look at it) to see how much you've spent in fuel. I'm always trying to beat my last tank and last MPGs.

I also calculate my MPGs the way Fuelly does-----miles divided by gallons. You drove xxx number of miles and divide that by how many gallons you put in.

I've gone so far in my hyper-miling to try and use the same pump at the same gas station. I can't Always do this but it helps some with a control. I also can't always fill up at the same time of day. But I know this and doubt that it would make a big difference in the scheme of things.

Does anyone have a SCANGUAGE II that they use? My wifes car has its own built in computer thingy taht show your current mileage as you drive. You'd be surprised how just a little lighter pedal pressure can make the MPGs go up but you still go the same speed. Every little thing can help in todays economy!----------DirtySCREW

 

The superchips programmer I just bought gave my truck a nice bump in fuel mileage as well as more hp and torque. I love it!

My truck has the same size tires and the maximum tire pressure on the side of the tires is 35psi.

 

Whats the problem? I usually get 28city and 42hwy


But seriously its time for efans

 

I've got an 03 with the v-6 and it likes 75 to 80 on the hiway for its best milage, got 23 mpg going to texas with 4 people and a bed full of christmas presents. Also drove the bosses f-250 with a 460 up and down calif i-5 best i got was about 11.4 but it liked 80 mph too. Look on your tires and air to about 3-5 lbs less than max. If the gearing isn't changed then measure the tire height and compare to stock.

 

In regards to the tire pressure, you need to see what it says on the sidewall of the tire and max them out. If they are an LT tire, you are way under and if a P size, yer over. I get better town mileage than you do hiway but I've got a 4.6. You might watch the tach and apply enough gas that the truck goes thru the gears but the tach never goes over 1800 rpms. Yeah, yer gonna have loads of morons blow past ya but they ain't paying the gas bill. There is a huge difference in the fuel mileage between 65 and 70 on my SCrew. Might wanna slow down a hair and give it a try. The spacer is costing you and bolts are not expensive and can be bought at most any auto parts. The duals aren't helping you either for fuel mileage. They're great if ya drive it on the floor but that won't get you much fuel mileage. The EGR system is setup around the stock back pressure which the duals have eliminated so it's running on the the rich side. A tuner might give ya some of that back but I would not expect for the fuel savings to pay for it.

 

WHOA! umm..no fords are more fuel efficient than Gm's