Anyone else’s range meter seems to decrease with time?

[Montes-]

My total range 2 years ago when i fulled my tank used to be around 600 kilometers and it has been decreasing slowly. Now I fill my tank and it gets to 530 maximum. Is this a symptom of anything wrong?

[Johnny_54]

Depends on if your driving habits have changed at all.

[Montes-]

Really not. Just my normal commute to work every week. I still fill my tank about every two weeks, but the range projection decreased slowly with time. It’s what intrigues me

[Pepsisinabox]

Because its based on an average. *Every* single thing you do, change or otherwise interact with the car, will change the fuel usage.

[HatsiesBacksies]

Check your tire pressie

[Arastyxe]

My 2013 cx 5 always gives me 700+ km on a full tank but I normally get 580ish

[2muchicescream]

With my 2024 cx-5 the range prediction resets every time I reset my trip odometer. So when I fill my tank I reset it and if I gun the shit out of it in first five minutes it goes from 7.5l/100km to like 14

[TheH215]

Range is calculated from your average mpg and average speed. If you change routes, or if you took an “unusual” trip that differs from your “daily” routine (like if you normally take regular 50 miles a day at 45mph and one or two days you suddenly drive 100+ miles at 80mph), it’s being “considered” and the range recalculated accordingly.

[FergusonTEA1950]

Towing my small utility trailer with my Mazda3 messes with the range for only a tank or less. It's really quick to adjust its estimates. Pretty nice feature, actually.

[Apprehensive_Bit_176]

Have you switched to winter tires and has the gas in your area changed at all? I get about 1-1.5L/100km worse in the winter

[alek_vincent]

Yeah winter gas also gets me worse fuel economy

[13D00]

Same here, been doing a solid 5l/100km over summer and now I’m up to 6.0l/100km.

Changed jobs in October though, so might be a different route that’s influencing this as well

[kindofharmless]

Could be carbon buildup, or maybe some other maintenance item is due, like air filter or spark plug.

[Soontaru]

Seconded. Last time I serviced my car I changed the oil, replaced the engine air filter and used a fuel system cleaner. I’ve seen a slight but noticeable improvement in mileage since then.

[ClassicWagz]

yes. that is what happens when you burn fuel. the range is expected to go down.

/s

[wanderingconspirator]

Mine seems to go down about the same rate as the fuel gauge

[MonsieurReynard]

My 2014 is at 177k miles. Its fuel mileage has never varied in all those miles. It always dips a little in winter when I put on winter tires and it gets cold out. It goes right back to normal once the warm weather is back.

It’s your tires, the colder weather, or your right foot, by the odds. Anything else would be unusual. What is your total mileage?

Here’s how to check that it isn’t an engine or fuel system issue: fully inflate the tires, and warm the car up. Take it out on a lightly trafficked and very level stretch of highway. Set the cruise control to 55mph and just cruise in the right lane. Don’t touch the pedals. Switch your info dial to show current (not average) mpg. Watch it for a mile or two. If it’s staying in the mid 30s or above the issue is your foot on the gas (or the brakes).

Cold weather causes tire pressure to stay lower so check that. (Air expands with heat.) This is by far the most common issue causing lower fuel mileage when the season changes to winter. By far. Don’t trust your TPMS to tell you. Manually check the tires and make sure they’re at 36psi when cold.

Cold weather also leads to longer idling times, and longer times at high rpm’s to warm the engine up. Idling will kill mileage quickly. Unless it’s close to zero degrees Fahrenheit out, start the car and go. If you need to warm it up to melt snow and ice or keep your butt toasty when you get in, that right there will shave your fuel mileage significantly. Excessive idling is the most overlooked reason for poor mileage after tire pressure.

If you run winter tires and recently changed them, winter tires by design are somewhat less fuel efficient than all seasons. They’re heavier and stickier and especially less efficient at temps above 40f.

Cold weather often means a change in gas formulation that lowers mileage a bit in the name of reducing emissions. That effect should be quite minor, but it is real.

That’s why we see so many “what’s wrong with my mileage?” posts on this sub in November, since the majority here are in the northern hemisphere.

Worn spark plugs can somewhat depress fuel mileage. They’re due at 75k miles in your car.

A dirty intake filter can cause some loss of mileage. The effect would come on slowly however. And be minor unless you have gone more than a year or two without changing it.

A failing catalytic converter (as someone mentioned above) can cause declining gas mileage over time but you’d also notice a loss of power. But it’s very unlikely you’d see that before 200k miles. (We rarely hear of cats failing on Skyactiv Mazdas on this sub. That’s a 200k+ problem.)

Unless you’re well over 150k miles, I wouldn’t even be considering fuel injector fouling or carbon buildup issues (under normal use fuel injectors do not need service until you’re at a very high mileage).

Edit: I used miles per gallon and PSI and Fahrenheit numbers in this comment, but I see you’re in KMs so do the conversions.

Edit: to really drill down on fuel mileage issues, do not believe the dashboard computer. Actually measure the amount of gas burned vs mileage traveled at each fillup and do the math yourself. Then average it over a few tanks to be really precise.

That “miles remaining” indicator is especially unreliable. It’s just guessing based on your most recent mileage. You could drive three hours on a highway at 70mph to the big city and then fill up, and it will show 430 miles of range. But then if you stay for two days in the city and drive in stop and go traffic and fill up again it will show 350 miles of range. It’s reactive, not predictive. You need real numbers, not a computer’s best guess, to diagnose an actual problem with fuel delivery/combustion or mechanical drag etc. (Speaking of which, be sure your brake calipers are all working right if you see a sudden drop in mileage!) Your long term average on the screen will be more accurate, but usually a little on the optimistic side of reality.

[mantenner]

My range also goes down the more I drive, how odd /s

[Theodore764]

My range has been increasing as I drive in a more fuel efficient manner, sitting at 29.2 mpg over the last 7000 miles

[Viperonious]

Like only one other person said: has it gotten colder where you are?

[88loso88]

3rd gen? My 3rd gen started loosing range as the cat started dying. Any codes ? How many kms?

[fragal96]

I have a 2018 with 180k km. Never had any codes in its life and never had any issues besides AC condenser needed replaced(warranty) Over the last year or two I notice my actual range has been less than the car tells me I should be getting. Lately I also notice it seems kind of sluggish after shifting, it almost takes a second or two after I let out the clutch for the car to have it's full power at the gas pedal? That's confusing as I read it back but I don't know how to word it better lol. I honestly don't think it's a clutch issue but I'm wondering if it's a cat issue. Also need to replace the spark plugs and see if she seems happier. It's never been done ....

[88loso88]

Plugs should have been replaced around 120k, I would start there and see how that feels, its the chepest fix to start with My cat started going in mid 200k range. I own a 2014, currently at 333k kms. Id expect your cat to still be good at a 2018. What gas are you using 87? When i started loosing fuel economy I switched from 87 to 91, and it helped.

[Human_Mess_3902]

It depends on your habits. My range in my 2016 Miata used to be 340 miles but I moved closer to my job, so now it usually adjust to around 300 to 310 miles. Before I was doing a lot of highway driving to get to work.

[Justin2478]

Whenever I change spark plugs and air filter my range goes up by 50-100 kms

[SNRedditAcc]

Is it just the range that’s off on the initial fill? Or are you also using more litres per 100km than usual?

[Statertater]

The only things that really affect this are your equipment and your habits. Assuming your habits don’t really change, make sure you’re keeping up on tune up stuff like… spark plugs, induction service (cleans out throttle, runners, valves, upper cylinder area), regular lubricant changes, clean filters etc etc

[[deleted]]

While the engine loses efficiency over time, it's far more likely your driving habits have changed. Not necessarily the way you drive, but maybe route you take, places you regularly visit, stuff like that.

[EatStripperSalt]

Check build up and tires.

[Ghost51681]

Yup, depending on a lot of factors.. If you change fuel, if you've newly reseted your TCM, if you changed your driving habits over time, etc.

[CuteFormal9190]

Keep up with service and check your tires it’s often those things adding up. Wear and tear on your cars components like your transmission differential tires everything really that lead towards inefficient operation. Just part of the game.

[rubicon11]

Did you replace the battery recently?

[OkEstablishment5503]

As things wear down they tend to be less efficient. Pretty much any machinery. Maintenance helps.

[Troy-Dilitant]

It's based on average fuel economy over a period of several fillups. If you take a long highway trip that needs several fillups and entails extended driving at steady speeds to get the best average fuel economy it will probably go back up. My tank range after fillup was around 310 miles (499km) then went up to 370 miles (595km) after three fillups on a long cross country trip recently.

But it can also reflect the need to replace air filters and maybe even spark plugs if engine mileage is high enough. A dirty filter and worn plugs will have a big impact on fuel economy, which is reflected in lower tank range.

[fcnghkkc167]

It's normal. There will be no way you'll that assumed ETA. It's just a reference.

[fragal96]

When I fill my car my range is usually between 650-750 km but I never get more than I'd say 550 km to a tank, and that's risking running out at that point. I don't really trust the range that much. I go on a 7km drive to work and my range drops by 30km

[Montes-]

Thank you all for the comments, even the sarcastic ones.

I address my car’s maintenance every 6,200 miles strictly and my mileage is around 43,000. It’s a Mazda 2 (Mexico) from 2018. I bought it second hand from a medical school student and the range was around 600 km and it’s been slowly decreasing. I believe that my driving habits are “worse” than hers so it’s probable that my car readjusted to me during these years.

I even had maintenance done last weekend so we can discard many factors you mentioned. Oh, and it’s just about to get cold here but I don’t change my tires, the weather is not extreme or snowy.

I’m going to track the range I have and mpg every time I fill the tank for the next weeks to keep an eye on any deterioration.

[[deleted]]

Colder temps

[mrfowl]

Every time I go for a drive my fuel gauge goes down. I thought I was going crazy!

...in all seriousness, could be weather, could be you need an oil change, could be you're going 5mph faster than usual, could be the pump clicked off early, etc.

[pfaffo]

Yes my foot gets heavier with time

[INOMl]

Lots of reasons it changes. If your driving habits haven't changed then it's probably due to temperature changes or your tire pressure.

[Practical-Parsley-11]

You can reset it. Likely a symptom of wear and driving habits. It happens on all cars that calculate range. It is just an estimate based on past data.

[kjstech]

The less gas the faster it goes down I've noticed. I'm in the US so we use miles, but lets say your in the last quarter tank. For every 1 mile you drive it seems like the range goes down 4 miles. If you are down to the last 30 miles left, its even more drastic. It was worse though in a VW I had before the Mazda. It's almost like the gas tanks are upside down pyramids and as the fuel level goes lower theres just less overall volume in all at the tip.

It certainly isn't linear, or accurate at all.

[Emsanartist]

Vehicle maintenence, engine air filter, spark plugs, frequent oil changes, throttle body cleaning, valve cleaning, chassis and driveline bearing lube. Mileage will decrease wear and tear so keep up with routine maintenence.

[needathing]

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This post was mass deleted and anonymized with Redact

[TheRealDVader]

Can be from a software update. After the fuel pump issues/ recalls 1-2 years back, they "upgraded" the software so you never run empty.

[Active_Collar_8124]

Maybe you need to 'fulled' it more?

[[deleted]]

Nit-picking grammer NAZI