To keep your mileage when servicing the O2 sensors, replace all four sensors and not just the upstreams. Quite a few think the rears are just cat checkers in these trucks. Not true, they are much more than that. Then you'll keep at the best it can do, IF your really attempting to keep it there.

 

Here's what worked for me earlier this year. I went from 12MPG to averaging 15.3 by doing the following:

1 - Ensure you're using the correct thermostat. 192 degrees F minimum, 198 degrees max. Installing the correct one for me helped a lot.
2 - Use the paper motorcraft air filter and make sure its clean. If there's an aftermarket air-cleaner/intake assembly on the truck, take it off and replace with factory.
3 - Search and destroy any and all vacuum leaks immediately if codes are thrown.

 

I once picked up 1.5 mpg or so just by increasing pressure in my tires.

running the front at 32 makes it ride better, but higher gives much better mileage.

some tires give better mileage as well.

 

Really? I've thought they just check cat fundtion and have never replaced them. What do they do? Where did you get this info if you dont mind me asking?

 

I'll trade you, I spend $150 in fuel for a week and a half lol.

 

Quote:

Originally Posted by jethat

Really? I've thought they just check cat fundtion and have never replaced them. What do they do? Where did you get this info if you dont mind me asking?

The rear (downstream) HO2S sensors are treated rather differently yes. The peak and low voltages are also continuously monitored, but if the monitor has not detected a peak or low voltage beyond threshold, then the fuel/air mixture is forced high or low in order to get the sensors to start switching. If this sequence does not 'shock' the rear sensor(s) into switching, then a DTC is recorded.
That's how it works. So forcing rich within threshold will spend fuel. As O2's age they get lazy....slow to switch. In turn, the engine will have more of an appetite.

This info came from Ford Motor US and UK sites. You'll have have to look that up yourself, I've already done my time doing so.

EDIT and BTW- IF you still frequent that other site I use to contribute to, before it was compromised by misinformation and lost it's popularity, -(lost a lot of good guys), lookup Steve over there. He knows the system well. If he's still around his user name was "projectSHO". Perhaps he can add more to it for yuh.

 

Pssht... Yeah.. Gas up here averages between $4-4.76/gal.

I think what Op is doing is great.

Free
- Lighten up on gas pedal. Pretend there's an egg under it and another under your foot.
- Remove all unnecessary crap from the truck. (Straps, hitches, toolkit, fine. get rid of the 50lbs of extra stuff you dont really need.)
- Proper air pressure in the tires. (Some like to overfill them a little. Door jam is minimum as far as I'm concerned)
- Use smaller tires. (If your using 37' super swampers that are 9-10 wide, perhaps the factory size is better)
- Remove any mods. (The rear spoiler on the truck cab and ground effects aint helping, neither is the supercharger and monster injectors and rails. )
- Keep near or at the speed limit. The faster you go, the more fuel you burn (Over 100kph anyway) There's a sweet spot in every vehicle where it will give you the perfect balance.
- Keep a log. Use an app like fuelly to keep track of your mileage and experiment with driving habits and free mods to see what techniques will net you the best fuel economy. Is it better to accelerate briskly and cruise at speed longer, or is it better to creep up to highway speed and then cruise shorter? Hard to say, this will help.

LOW COST
- Use the recommended fuel that the manufacturer states. Putting "Gold" fuel into a truck that doesn't need it ain't helping. (Yes, I carry certification from the Canadian Professional Petroleum Institute and work on fuels from diesel to NATO f37 jet fuels. If you're in Canada, unless your engine needs it for compression, don't waste money on premium fuels.)

- Regearing. Low cost is subjective dependant on materials and needs. If you're doing a lot of empty highway miles, a different rear end could help your fuel economy some. Perhaps. Maybe.
- Keep the engine tuned up.


High cost

-Engine replacement. If your old engine is pooched, or on its way out, consider swapping it out to a better model. Maybe instead of a 5.4L, perhaps the 4.2 might work better if your not towing. Maybe you have the 4.2 and do a lot of towing and the 5.4 might be a better fit then instead of running the nuts out of the 4.2. Your situation will dictate.

-Aero mods. Lowering a vehicle -some- will help with economy. As will the addition of air dams and shutters in the grille.

-4x4 to 2wd modification. Live in Arizona with little to no snow and dont go 4x4ing? Perhaps consider converting the trucks powertrain to 2wd? No tcase to run, no second diff (or front cv axles depending) to spin.

 

The efans are worth .5 mpg but you can build a setup much cheaper than that. I don't think I have 100 in mine.

 

Cost of mods? lets say $3000 for all those mods. Seems a reasonable price.

Now do the math.

You're at 16mpg now.

You won't get 22mpg =- not in that truck - lets say you see 19mpg. You gain 3mpg.

You need 1000 gallons to break even. How many EXTRA tanks at 3mpg is that? 300?

333 actually. times lets say 20 gallons per tank. = 106,000 miles. . . .

ok - go for it.

 

My cure for the MPG blues..... The Silver Bullet....