Unexpected Gas Mileage Drop

[BAT]

So pretty much since I bought my JT back in 2020 it has stayed around the 16.5-17 mpg doing just local driving. But in the last 2-3 months it has fallen to around 14 mpg and stayed there. I have not done anything to the truck, nor have my driving habits changed. Has me kind of puzzled as to such a drop after being so steady on the mpg over the last 3 years.

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[Gren71]

fuel injectors? spark plugs? air filter? tire pressure? new tires(with a different weight or tread)?

Just off the top of my head any of those could have a negative effect on your normally steady mpg

 

[ShadowsPapa]

Check your air filter as one simple fast idea.
Otherwise, all sorts of things can happen to cause mpg to drop fairly suddenly - some are simple, some will require some serious diagnosis.
For example - O2 sensors - but you need to know what the normal range is for you to know where they stand now.
Look at sensors like the O2 sensors, MAP and so on and see what's in normal ranges.
It's not like a carbureted engine where you can say it's plugs, carburetor, etc. and quickly have it figured out.


Ambient Air Temperature: 12.00 Deg.C
Short Term Fuel Trim - Bank 1: 12.49 %
Long Term Fuel Trim - Bank 1: -3.13 %
Short Term Fuel Trim - Bank 2: 9.37 %
Long Term Fuel Trim - Bank 2: -7.04 %
MAP Voltage: 1.96 V
MAP: 46 kPa

You may be in for some deep diagnosis.
You may find something simple - plugged up air filter, maybe try some injector cleaner - or find out some sensor is misreading things and causing an overly rich mixture.
Anything that gets mentioned is really going to be just tossing spit balls at the wall and see what sticks. Unless you have some real readings on things, it's just going to be a list of things that may cause sudden drops.

 

[BAT]

Yea I was just thinking the other day to maybe add some additive to the fuel to see. Will check my air filter. I have a friend who has been my mechanic for going on many years. Will get him to take a look at it if it doesn't swing back.

 

[BAT]

fuel injectors? spark plugs? air filter? tire pressure? new tires(with a different weight or tread)?

Just off the top of my head any of those could have a negative effect on your normally steady mpg

I haven't put anything on it in regard to new tires, etc. I did just put new Fox 2.0 shocks on it but that was just a few days ago and this was going on before that.

 

[Pakdoc]

My stealer advised me I'm due for the 50k emissions treatment for $325 next oil change. But I think my mileage is pretty good with stock 33's and always question "emissions" service.

 

[smlobx]

How many miles do you have on your truck?

 

[BAT]

How many miles do you have on your truck?

32000

 

[BAT]

My stealer advised me I'm due for the 50k emissions treatment for $325 next oil change. But I think my mileage is pretty good with stock 33's and always question "emissions" service.

I would never see that gas mileage unless I lived on the freeway (LOL).

 

[Pakdoc]

I never got into the 19's until 50k, just tire wear and is my daily driver I guess.

 

[TheRealStreetcommander]

Another thought, Is it possibly a result of your area suddenly electing to use a winter blend of fuel? My region does and I loose 2mpg when my filling stations are on winter blend. Your local jurisdiction may have pulled shenanigans and upped your ethanol ratio as well. Ethanol has 1/3 less energy per volume than straight gasoline. So, even a 5% addition of ethanol will have a noticeably negative effect on your MPG.

"According to UNdotORG, around the world 25,000 humans die every day due to starvation... In other news, US liberal governments mandate using corn for the production of ethanol to be added to fuel. This while US gasoline is plentiful, less expensive than ethanol, and more efficient."

Oh well, F those people right? Our hubris ambitions for allegedly cleaner air are more important than 25,000 people a day. It's just the poors that die anyway. Right?

 

[BAT]

Another thought, Is it possibly a result of your area suddenly electing to use a winter blend of fuel? My region does and I loose 2mpg when my filling stations are on winter blend. Your local jurisdiction may have pulled shenanigans and upped your ethanol ratio as well. Ethanol has 1/3 less energy per volume than straight gasoline. So, even a 5% addition of ethanol will have a noticeably negative effect on your MPG.

"According to UNdotORG, around the world 25,000 humans die every day due to starvation... In other news, US liberal governments mandate using corn for the production of ethanol to be added to fuel. This while US gasoline is plentiful, less expensive than ethanol, and more efficient."

Oh well, F those people right? Our hubris ambitions for allegedly cleaner air are more important than 25,000 people a day. It's just the poors that die anyway. Right?

Can't say if they did or not but we don't get much winter here in Texas and since I have been driving the truck and buying gas from the same places over the last 3 years and its been consistant seems like it maybe is something else but will see when I have more time to look into it

 

[K1w1t1m]

I'd suggest trying a different gas station.

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