On my truck, I'm only getting about 11-13 MPG. But on the forum, I've seen some people with 17-20 MPG on my engine and similiar year truck.

My question is, what are yall doing to get such good MPGs out of our trucks?

Is it something wrong with mine?

Help, I'm having to fill my rear tank every Friday/Saturday.

 

Pull the codes to see if there is anything wrong.

You could also do a tuneup. Cap, rotor, spark plugs, plug wires, probably even the o2 sensor.

 

keep your foot out of the firewall...

 

I'm getting around 19 in my '91 (ballpark, I'm actually recalculating this week)...and there are a few things you can do to improve things.

Mechanically: fuel system cleaner, good tires with proper pressure, good spark plugs, clean air filter, clean fuel filter, and maybe a higher grade of gas, good distributor and coil (I just replaced the distributor in mine, lots of scoring on the old points). If you live in an area with good weather, keep the windows up and the air off (harder than it sounds these days, I leave my windows down all the time).

You can also use good driving habits. Keep it at the speed limit or a bit lower. Listen to your truck. If the engine is revved up (say when you are doing 60 down the highway), cut back on the speed and let it slow down some. Or, if the speed limit allows it, see if you can go a bit faster until the tranny shifts again. Lower RPM, lower consumption. Accelerate slower. If you are driving in town, you probably aren't going to get to the limit for long anyway, so take a bit more time to speed up (believe it or not, most people don't have to drive like they think they have to 'get there first').

But also, while it will get 'good' mileage, it's a big truck, it isn't going to get 'great' mileage. And if you are hauling a load...well, that's gonna make it worse.

I bet the long-timers here have more tricks to try.

 

My '89 F150 2wd, bone stock gets 11-13 around town, and i've hit 18mpg on the highway (driving 55mph)

300-6 C6 3 speed.

 

X2...................

 

I'd say a tuneup is in order. If it's the 300 in your sig, I'd expect it to do better; that mileage is more in my range of 'good' to 'great' fuel economy.

I would add to the list that Tolen gave you to check your catalytic converter, and don't buy the E10 blend if you're looking for better mileage. My truck gets 1-1.5 mpg lower with E10 while my '03 Focus ZX3 takes almost a 5 mpg hit from E10.

 

Most people lie about their mileage, are too incompetant to calculate correctly, or use "highway" claims in place of average (which is the only one that matters). . .

There are a lotta things you could do to increase mileage. A long tube header with no cat or a free flowing cat would prob be the single most substantial mod. Synthetics in the drivetrain is another easy one. Keep modest size tires w. Proper inflation and highway tread pattern. There are a ton more things that range from head porting to compression increases and even turbocharging. . .but are all time consuming n most people wouldn't bother goin that far.. if you achieve 15 average that'd be decent.

 

dont let the big six lug. my truck seems to lug a little while im doing 55 in 5th gear (i have a 2:73 rear end). i get equal or better mpgs doing about 65. i get 10-12 mpgs around town because i drive too aggressive, and i have come to accept that.

 

The truck has all the aerodynamics of a two story house...you're NOT going to get good gas mileage, no matter what you do. The best thing to do, if you're worried about MPG...park it and find a Honda.

 

Well, yes of course I don't really care about MPGs, I mean after all I did buy a truck, my wallet does, and until it gets fatter (wallet), I'll try not to complain as much.

As for the tuneup the cap, wires, and plugs are about 6 months old. The only thing I didn't replace is the rotor.

And I guess I could replace O2 sensor because last time I pulled the codes it said something about running lean. But with that being said, I also think my cat is clogged and i have a exhaust leak after the O2 sensor, so would it be better to delete the cat? Cat deletes are cheap.

I do tend to drive a bit aggressive, but not all the time. I got the figure 11-13 MPG while I was BABYING my 300 for a whole week, with pedal to the metal everyday I get horrible MPG.

Windows are always down, living in South Texas, it ain't easy keeping them windows up, also A/C is never used.

I think the tires are undersized than stock, well as far as width. I run 30x9.5x15s which are A/Ts.

So I don't see what the problem could be? Cat? O2 sensor? Possible EGR valve restrictor plate?

 

The basics...

Plugs, rotor, cap, wires, good oil, O2 sensor, and properly inflated tires. If you go to a smaller diameter tire, your mileage will improve. Vacuum leaks, however small, could also bleed you mileage results.

Check your speedometer as well...mine has been a constant 5 mph off for years, which changes the odometer as well.

You drive with the windows down...do you have a sliding rear window? if not, that could effect it as well.

Do you drive with the tail gate up? if so, drop it or delete it and add a net.

Also...is the gas you use good gas?

I'd also to a Seafoam treatment...follow the instructions and suck the fluid in with the brake booster vacuum line. If this has never been done, contact NASA and warn them you're about to do it, as the smoke cloud will be seen from the space station.

Removing the cat will give more power, but isn't the wisest thing to do for MPG.

 

I usually try to do system injector cleaner about every month, granted that may be a bit excessive but it seems to help with keeping the engine running smoother as I don't know how often it was done by the PO so i figure I would do my part to keep the engine clean and running smooth

 

Ok everything is good except rotor and 02 sensor. (For sure changing rotor soon)

No sliding rear window, wish I did but no.

Tailgate is always up, most of the time I have stuff back there, but light stuff that I don't want to slip out if tailgate is down.

At the moment I use 87 since it's summer and the prices are a bit up, but usually I use 93 and man I feel the difference, LIKE BIG difference. (But that'll be for a different thread)

Ah, yes the Seafoam, my friends have recommended that to me as well as the Marvel Mystery Oil. I have used Marvel Mystery Oil several times and occasionally the Injector Cleaner. (This was when I cleaned both tanks)

But I think it has to be something with the engine, because I used to run 31x10.5x15 (not that much of a difference) and still got same MPG.

 

My 5.8 gets 10-12 mpg. I've hit 20-22 with my old (sold unfortunately) 81 3/4 T with a 300 6 and a manual tranny. My current Ford is a 94 supercab longbox 4x4. I love it but would like better mpg too. Oh, and it's got the E4OD trans so a manual trans would prolly get a bit higher mpg.