My mileage s*cks

[James Morse]

Engine has plenty of power, starts right up, isn't throwing any codes, but I'm getting like 10mpg, now that is all city driving but still!! When gas was a couple bucks plus I figured wtf but now...

184k. I had it a few months, fixed a bunch of stuff, oil looked like it had just been changed when I got it. My question: what should I do, generally speaking? plugs... oil/filter change I suppose.. maybe injector cleaner (Seafoam? other?). What else to check? I don't want to spend more on parts/my labor than I get back in gas savings, of course if anything aint right I want to set it right... seems like I ought to get maybe 12-13mpg in town? Sure would appreciate any help, thanks.

 

[alwaysFlOoReD]

O2 sensors? They last about 100,000 miles.

 

[19Walt93]

Or try driving it somewhere with less traffic. While you're sitting at those red lights you're getting zero mpg.
I averaged 16 mpg all last summer with my 351 swapped 93. I drive like an adult most/some of the time and Canaan does not have a traffic light.

 

[Lefty]

I'm getting about 21.5 in winter in the city. My average driving speed is 19 mph. I've got 148, 000 miles. I drive on oversize tires

This year I installed a K&N air filter, put in fuel injector cleaner, synthetic oil, replaced the spark plug wires, put in a computer chip, and plumbed for dual exhausts. I did all this over a span of a few months, so it's hard to tell which improvement makes the difference. My guess is the air filter and the dual exhausts.

As soon as the weather warms, I'm switching to an electric fan.

The average mpg for a regular cab Ranger is about 17.5 which weighs in at almost 500lbs less.

Also, if your truck has been lifted, it will have more wind resistance on the bottom side.

Maybe this helps.

 

[19Walt93]

My 04 an 11 4x4 supercabs did 16-18 commuting to work about 5 miles on the highway and 8 on secondary roads, I could squeeze out 21 highway before ethanol and at best 19-20 feeding them E10.

 

[James Morse]

I first suspected O2 sensors but with no codes thrown wouldn't that be contraindicated? ie if bad wouldn't it throw a code? should I change them anyway? it was my first go-to but with no code I figured they must be ok...

thanks everyone and I will go over responses more tomorrow. it sounds like I should be doing better than what I am as to the mpg.

 

[Uncle Gump]

I just checked my mileage the last fill up. 06 4.0L 4x4 and it's been cold so I've been remote starting... 15.8 mpg.

 

[Roert42]

I first suspected O2 sensors but with no codes thrown wouldn't that be contraindicated? ie if bad wouldn't it throw a code? should I change them anyway? it was my first go-to but with no code I figured they must be ok...

thanks everyone and I will go over responses more tomorrow. it sounds like I should be doing better than what I am as to the mpg.

There is a threshold we’re the ecu will adjust for the readings from the 02 sensors, that why they are there. If they’re worn out and giving bad reading they won’t give a dtc until they are super bad.

 

[O No 3.0!]

Check your air filter, spark plugs, tire pressure & your cooling fan. All these things can contribute to bad mileage. 02 sensors can add to the bad mileage as well, but i wouldn't change them until you've eliminated everything else.

 

[55trucker]

LOL.....put one of these

under your throttle pedal

 

[Lefty]

Sometimes, especially when an engine has logged over 100,000 miles, it is not just a matter of one thing. Mine ran better with injector cleaner. There are Seafoam treatments for the engine and the oil too.

 

[RonD]

Computer has no comparison for O2 sensors, they are, as far as the computer is concerned, "the word of God"

O2s use a chemical to detect Oxygen in the exhaust, NOT FUEL
O2s generate their own voltage using the chemical reaction
0.1v is high oxygen(lean)
0.9v is low oxygen(rich)
As the chemical runs out(100k miles or 12 years) the O2 starts to show a lower voltage(lean) so computer ADDS MORE FUEL, which is not really needed, so MPG slowly starts to go down, un-noticed at first
Computer has no idea engine is actually running Richer than it should, it has nothing to compare it to

So computer relies on the owner/driver to change the O2 sensors as needed for best MPG and running
Kind of like changing the oil, there is no "change the oil sensor", well not on Rangers, lol, some car do have a mileage settings that will cause a "Change oil soon" indicator
O2s are the ONLY sensors that WILL wear out, on any vehicle

Until the O2s stop changing voltage the computer has no idea there is a problem, so no reason to "set a code"

By the time you get an O2 sensor code from old O2s, you will have probably spent an extra $500 in gasoline you didn't need, even more now that gasoline is so expensive
So they are basically FREE in the fuel savings over the next 100k miles or 12 years, and even make/save you money

 

[94' Ranger]

I'm a little late to the party but here's my gas mileage over the last ~2 years in my 1994 3.0 Ford Ranger. Was 99% stock when I bought it, made a few changes over the last two years like new shocks and springs and deleted my AC.


Gas mileage

15.96
17.90
15.92
15.59
16.46
16.32
16.43
Bought four new Falken AT3 235/75R15 tires, biggest I could fit without major rubbing.
14.62
13.68
15.12
15.24
14.94
14.34
16.78
14.36
13.54
14.76
14.33
16.82
13.32
13.74
14.09
13.19
15.91
13.65
14.30
13.38
13.16
12.28
12.40
12.14
12.09
11.23
EGR FIX -- My EGR valve had so much carbon buildup in my intake it couldn't breath anymore.
14.44
14.36
12.89
14.45
14.34
13.83
BOUGHT 6 NEW FUEL INJECTORS
15.07
16.43
16.70
16.82

 

[Lefty]

I'm a little late to the party but here's my gas mileage over the last ~2 years in my 1994 3.0 Ford Ranger. Was 99% stock when I bought it, made a few changes over the last two years like new shocks and springs and deleted my AC.


Gas mileage

15.96
17.90
15.92
15.59
16.46
16.32
16.43
Bought four new Falken AT3 235/75R15 tires, biggest I could fit without major rubbing.
14.62
13.68
15.12
15.24
14.94
14.34
16.78
14.36
13.54
14.76
14.33
16.82
13.32
13.74
14.09
13.19
15.91
13.65
14.30
13.38
13.16
12.28
12.40
12.14
12.09
11.23
EGR FIX -- My EGR valve had so much carbon buildup in my intake it couldn't breath anymore.
14.44
14.36
12.89
14.45
14.34
13.83
BOUGHT 6 NEW FUEL INJECTORS
15.07
16.43
16.70
16.82

That's pretty close to what Ford advertised and what this website shows: https://fueleconomy.gov/feg/bymodel/1996_Ford_Ranger_Pickup.shtml

It's also interesting to see how mileage changes with maintenance and modifications like bigger tires.

 

[K Thompson]

I have a 2003 3.0 5 speed stick stock tire size. I keep the revs at or below 3000 rpm. Worst mileage was 19.5. Usually gets 20 to 21 driving in DFW.

I have a friend who has a 3.0 Ranger also and his mileage went south. They discovered the thermostat was faulty and the engine get up to operating temp.

Best of luck finding the problem!!!