Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [fuel-consumption]

Use for questions related to fuel economy.

Fuel efficiency measures how far you travel on a given amount of fuel. It is typically measured in Miles per Gallon (mpg) or Kilometres per Litre (km/l)

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Do cars consume less fuel when in Neutral?

Imagine we're going down a hill and we're driving a manual car. There are two situations: If I put my car in neutral it will go downhill without any need for the injector to squirt fuel into the system, just enough fuel for the engine to idle. I…
Andrew Ravus
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Is idling bad for your engine?

If I sit in my car for 30-40 minutes with the AC and the car idling, does that "hurt" the engine, or does it simply waste gas and pollute the air? Would it be better if I turned off the car? A similar question was asked, but it never addressed…
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How do the latest automatic transmissions match the efficiencies of manual gearboxes?

Most people know that for old or even somewhat old cars, manual transmissions are more efficient. Recently automatic cars have become almost as efficient or even as efficient as manuals. I was recently reading an article by Road & Track magazine…
user180969
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Does flooring the throttle while traveling at lower speeds increase fuel consumption?

I've noticed that in a manual transmission vehicle when going uphill I have two options: Downshift and press the gas more Stay in the same gear and press the gas more I haven't measured it but typically in the higher gear I end out flooring the…
Wayne Werner
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What does Honda's 'Econ' button do? Does it truly improve fuel efficiency?

I recently bought a Honda Civic that had this in the car: I have no idea what it does, and how it's supposed to help. Even Honda's website is ambiguous, just using a lot of fuzzy words to describe what it does. From the website: Econ Button and…
yuritsuki
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At what time of day/temperature should I refuel my vehicle?

I mean, should I refuel my vehicle in the morning? The reasoning is simple, in the morning the temperature is low and the density of the fuel would be higher and I get more energy per litre(or whatever metric system you use). But in afternoon, or…
RogUE
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Are there any advantages of idling a vehicle vs. turning it off and back on again?

I was sitting outside, eating my lunch the other day, and a small bus (you know, one of the short ones) pulled up to the sandwich shop I was eating at. I noticed that the driver got out of the bus, ordered her food and waited for the roughly 10…
James Mertz
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Will higher octane fuel improve towing power?

According to Will higher octane fuel improve gas mileage? higher octane fuel does NOT notably improve fuel efficiency. Will higher octane fuel, increase power while towing? I looked online and found two different answers. Will using a higher octane…
James Jenkins
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how to optimize fuel consumption by changing the rear differential ratio?

Is it possible to improve the fuel consumption (decrease it) in my van by changing the rear differential ratio? I would like to optimize it for low-speed driving about 40 km/h (25 mph). Is it true that the rear differential ratio is optimized for a…
ria
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Does accelerating faster worsen fuel efficiency?

I've often heard that accelerating harder makes for bad fuel efficiency, but have yet to be given a sound explanation of why. Naturally this makes me question this advice. Now obviously when you accelerate harder, more fuel is being pumped into…
andrewb
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What makes two-stroke engines less fuel-efficient than four-strokes?

It is a commonly-held belief that two-stroke engines are less fuel-efficient than four-stroke engines, and some example BSFC figures appear to confirm this as well. But what is it that causes two-strokes to be less fuel-efficient? I used to believe…
Zaid
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Is shifting to neutral on a decline more fuel efficient than keeping the gear engaged?

I always had the habit of shifting to neutral on long declines and using the brakes to slow down as needed. Intuition made me believe I'd be saving fuel as opposed to keeping a gear engaged. However, I noticed that the on-board fuel consumption…
Smig
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How much does spark plug gap affect fuel efficiency?

I've read conflicting reports regarding how plug gap can affect fuel efficiency. For example, I've read that too small a gap won't cause a clean burn, or that too large a gap can cause misfires due to the voltage being insufficient to jump the…
Robert S. Barnes
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What can cause a car to consume more fuel?

All over my long driver career, I had 4 cars (5 years). I always compare my fuel consumption with other people who have the same car. 3 times out of 4, I found out that my cars were consuming more fuel then others (I like buying car in poor…
Jean-François Savard
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What is most fuel efficient at 130km/h?

Suppose a very hot summer day, driving on a long straight highway at 130 km/h. What is most fuel efficient solution : Driving with AC on and closed windows? Driving with AC off and four full opened windows? One uses fuel for running AC, other uses…
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