Gas Mileage

[91 blue ranger]

Hey everyone I was just wondering what gas mileage you guys are getting. I am getting 14.5 mpg and I have 31 inch tires, 4.0 engine, 2 inch lift kit, and 3.73 rear gears. What can I do to improve my gas mileage? Thanks

 

[sgtsandman]

I’m seeing about 17 on average right now with the winter blend gas. Of course, the roof racks and the weight of the extra gear I lug around all the time aren’t helping either.

My truck is setup somewhat similar to yours minus the lift.

A lot of little things can help with mileage. I run fuel system cleaner in the tank twice a year. Clean the throttle body once a year. Make sure your MAF sensor is clean. Check your tire pressure (I’m running my KO2s at 36 psi). Is your truck OBD Ii? Check for pending codes.

Now, with all that being said, looking at the year of your truck, you probably have the 4.0 OHV. Mine is and SOHC, so there may be some fuel efficiency differences between the two.

 

[91 blue ranger]

. Is your truck OBD Ii?

Sorry dont know what this means.


And Yes 4.0 OHV and 5 speed manual.

 

[sgtsandman]

Sorry dont know what this means.


And Yes 4.0 OHV and 5 speed manual.

Does it have a trapezoid shaped plug under the dash on the driver’s side? If so, it’s OBD II. OBD means On Board Diagnostic.

If not, it’s OBD I and I don’t remember where the port is.

 

[91 blue ranger]

Oh thanks will have to check to morrow. And It also lurges at low rpms. Like 1000 rpms or a little faster. Like in 3rd gear .

 

[91 blue ranger]

Oh yeah did not mention that Ihave no engine codes

 

[adsm08]

I have the same setup and get 17 ish regularly.

When was the last time you did a tuneup?

 

[91 blue ranger]

Never lol. Will probably get plugs and wires soon.

 

[sgtsandman]

It sounds like you have some preventative maintenance catching up to do. Chances are good that your mileage will improve once you get that caught up.

 

[Bgunner]

Being a 91, running the box style body, your fuel mileage will be worse than @sgtsandman 's and closer to @adsm08 's mileage. To get the best mileage possible keep a fresh tune up in it and remember that how you drive, aggressively or conservatively, will affect this number greatly.

Being a 4wd you will see less than what a 2wd will see and that if your rear brakes are adjusted to tightly will also lower your MPG. The latter will be depend on how recently the rear brakes were done, mechanic dependent of course.

you should see 14-17 MPG dependent on driving style, any thing less should indicate an issue somewhere.

 

[MikeG]

That's about what I was getting in mine for years. Are you correcting for tire size when you calculate mileage? I bumped up tire size from 26-ish inch factory tires to 29-ish and the odometer was (is) off by about 10 or 11 percent, that's checked against interstate mile markers on say a 100 mile stretch. The lift doesn't help things either (also lifted about 2"). 3.55 rear end and 2wd, but I keep a toolbox on the back and so between 200 and 300 pounds of extra crap in the truck.

Anyway even correcting mine for the odometer being off, and decently tuned up, with the 5 speed auto it was rare to break 15 mpg.... till I recently ran a bottle of stuff called "cata-clean" (I think) that I found at Autozone. Mileage jumped up to 17-18, immediately. 20+ year old cats may not be flowing too well.....

Hope that helps.

 

[91 blue ranger]

I think my speedometer is right. I checked it with a app on my phone. I can go 55 at just rarely under 2000 rpm.
What all is included in a tune up? Plugs, wires?

 

[sgtsandman]

I think my speedometer is right. I checked it with a app on my phone. I can go 55 at just rarely under 2000 rpm.
What all is included in a tune up? Plugs, wires?

It depends on the engine and how it’s setup.

Plugs and wires are part of it. Don’t cheap out on them. Motorcraft or Autolite for the plugs. Use only what is recommended getting fancy plugs often just make your wallet lighter and not much else. Don’t forget to check the gap. They can be off from being dropped or rough handling during shipping.

The same goes with wires, don’t go cheap.

Does your truck have a distributor? If so, it’s time for a rotor and cap. The contacts oxidize and corrode over time.

Your timing might need to be checked.

Change the PCV valve.

Change the fuel filter.

Take a look at the air filter. If you can’t see light through the element, time to change it. If the engine can’t breathe well, it will effect your fuel mileage.

I already mentioned fuel system cleaner and cleaning the Mass Air Flow (MAF) sensor. Cleaning the throttle body or carburetor too.

I think that about covers the main things. Someone will chime in if I forgot something.

 

[91 blue ranger]

Ok thanks I will look over it.

 

[rubydist]

The tire / axle ratio combination you have is not optimal. For 31" tires, you should have 4.10 gears. The engine would be at a more efficient operating situation than what you have now. Based on my past experience, you could be getting close to 20 depending on the combination of city/hwy that you do and how hard you mash on it leaving the light.