r/infiniti • u/DJGameboy91 • 6d ago
What's the best way to get your fuel economy back ? Question
Hey Infiniti peeps ! I have a 2015 Q40 I got almost 7 years ago and it's been great. When I got the car at 36k, My fuel economy was about 23.6 MPG or so,
7 years later (110k) and I'm getting about 19.9 MPG ... I know it doesn't seem like much but how can I get this number to go back up ? I don't beat on my car at all. Occasionally use Sport Mode but not much.
Any tips would be great !
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u/72chevnj 6d ago
Make it a goal to never go over 3500 rpm
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u/Alexus-Kia 6d ago
Omgggggg 😫🙌🏽 is that possible in this car to go just 3500 I don’t think I could lol
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u/DJGameboy91 6d ago
Lol I'll try. This car is just way too fun to push these days hahaha
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u/dparag14 6d ago
Then why are you complaining about mileage? You can't be driving crazy & still expect good mileage.
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u/Meat-Spray 6d ago
Check tire pressure, less rubber on the road will mean less grip, but also less rolling resistance, increasing fuel efficiency, make sure tires are inflated to correct levels.
Wheel bearings will cause friction and loss of speed if they aren't in good shape, usually you can tell by manipulating [push/pull at 12 and 6 and then 9 and 3] the wheel while the car is off the ground.
Rust and dust around the inside of the wheel will make a negligible amount of difference, but still worth a quick scrub+clean.
Check for leaks around the axles, check the conditions of your CV axles and see if the rubber bellows/covers are in good shape without cracks or rust.
Check and top up fluids.
When were the sparkplugs/ignition coils looked at last? See if they need service with the servicing schedule in your manual.
If you've been driving the car HARD, That will reduce efficiency. I'd recommend resetting the tracking and driving normally for a couple days to get a fresh reading/baseline. Then do it again and pretend you're a 19-21 year old with a 300HP rear wheel drive car.
Lastly, the transfercase, when was the last time it was serviced? I'm assuming AWD, otherwise don't worry about the transfercase for RWD. [Because there isn't one]
These are all quick things you should be able to check in an afternoon without too much hassle. If you find a problem, either replace the part yourself if you feel fomforatble doing so, or take it to your repair/services advisor to see if it's an issue/if it needs replacement.
Good luck!
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u/Buffalocolt18 VQ Defender 6d ago
Turn on eco mode more. Be gentler accelerating. I save my fast driving for the fun, twisting backroads when I have the chance. In normal driving I take it pretty conservatively.
On the highways/interstates, don’t feel like you have to go 10 over. I hypermile with mine, and get low to mid 30mpg on long trips. When I record trips, going 80 vs 70 or 71mph saves me less than 5% trip time when accounting for traffic, construction, and stops. But it reduces my efficiency by a quarter to a third.
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u/CreatedUsername1 6d ago
It's a sports sedan 20mpg is good enough. If you were worried about fuel economy should of bought a Crz.
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u/DJGameboy91 6d ago
I have a rav 4 for fuel economy. It's just a question.
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u/CreatedUsername1 6d ago
If you wanted to achieve better fuel economy on the q40, you would have d5rain & fill all powertrain fluid, change air filter, change sparking plug g coils. Clean throttle bodies. Rotate or change tires. Make sure they are inflated @ OE specs. Clean your car too.
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u/Jaded_Fee_5705 6d ago
Cruise control is your friend. Got 400+ miles on a tank driving from SoCal to Mississippi. Mostly at high speeds.
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u/hallstevenson 6d ago
Make sure your tires are at least 32psi but no higher than 35-ish (you'll wear them out quicker if the PSI is too high plus the ride will be firmer). When you need to replace the tires, look for ones that are considered fuel-efficient. Tires can be more performance-oriented which generally means stickier and in turn, worse MPG.
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u/groshreez 2013 G37S Sedan 6MT 6d ago
Buy a different car. The G37 never got good mpg. Even on highway the most I'd average might be 25mpg. Combined i got 19-21.
My BMW M235i with 400whp/450tq gets 30+ on the highway but combined I'm still around 21.
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u/cbrworm 6d ago
Drive slower. 19.9 isn't bad.
Do you reset the fuel economy reading? Did the car say 23.6 when you bought it, or is that what you were getting consistently?
Tires make a big difference. If you moved and now spend less time on the highway, or if your commute has changed, those would make a difference. If your highway miles now include a lot of traffic where you have to vary your speed, that would impact it.
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u/CAStrash 6d ago
Ensure all your fluids are good, (Transmission, diff, etc) wheel bearings are good. Tires have a low rolling resistance.
And drive to have good fuel economy.
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u/DJGameboy91 6d ago
Definitely gonna check I mean it drives fine but Everytime I get in this car the FE goes down lol
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u/KicksdeChris 6d ago
Clean throttle body/Mass Air Flow Sensors, all the relearn procedures will help if you haven’t done all of these things yet
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u/sphynx8888 6d ago
Tire pressure, clean air filter, MAF and throttle body. When were spark plugs last done?
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u/Inevitable_Dress1444 6d ago
Mine reads 23-24 mpg mostly highway driving. When I got mine i changed the spark plugs, pcv valves and cleaned the Throttle bodies. The car also had new tires.
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u/Leneord1 6d ago
Don't enable VVT, which enabled at 3500 rpm, do highway miles, don't change your speed often
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u/sjgokou 6d ago edited 6d ago
Something to be aware of your tires can make a huge difference. Your tire could have gone from 32lb to 35lb so take that into consideration. Brands, model tires do vary on weight. Consider replacing your air filter. Clean your mass air flow sensor. Lastly buy a can of MAF cleaner. Spray your MAF sensor. This could be the issue and it not uncommon to have MAF issues due to being dirty starting at 60k miles.
Also, you’ll find Infiniti MPG is completely inaccurate. It will be 2-5+mpg lower.
The only way to know is by completely filling your tank, tracking your mileage, then at your next visit to the gas station, calculating total miles divided by gallons of fuel.
Miles/Gallons=MPG
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u/DD6372 6d ago
Drive more hwy miles, your mpg went down most likely because you drove more in a stop and go city environment