my nissan micra now uses more fuel than before. ie before 10lits per 100miles now 10lit goes 75miles. why?

Answer 1

Your car may need a service, oil/ air filter, maybe the tyres are deflated slightly, have you put a roof rack on it. Are driving it faster or doing more short journeies start stop. start stop or turning the ignition on more as you start it up. Maybe it's the automatic choke. maybe your mat is resting on tha acceleraator causing idle to increase slightly. are you carrying more weight in the boot etc.

Answer 2

All cars use more fuel in cold weather because cold starting requires excess fuel, however to maximise mileage check and if nescessary replace the air filter and if it is overdue for plugs or an oil change whether from age or mileage get it serviced.
To check gas mileage fill up at your favourite gas station, and fill to the top of the tank, record the milage and drive until near empty fill up again ideally from the same pump, fill to the top of the tank again and record the mileage, quick calculation gives the miles then divide the miles by the Gallons and that gives the mileage, if you record this in a book for each fill up you are a) sad and b) can check if the mileage drops off, which can show up a displaced vacuum advance lead on some cars or a rag sucked into the air cleaner.

Answer 3

Well how old is your car? A few preventive maintenance thing my apply that you haven't done. You may need to change your fuel filter, Or get a transmission filter, and pan service. Because maybe your transmission isn't shifting like it used to because your filters are restricted. A top end cleaning may help too. Get the throttle body cleaned and an induction service and adding a good fuel injection cleaner to your tank may bring back the miles you've been losing. I suggest Lucas brand fuel injector cleaner if you do....And get the 2nd biggest bottle. It will give you about 10 uses out of it because you only need 1 ounce per 10 gallons of fuel.
Also poor tire inflation can be a factor.OR maybe you changed the type of tire that is on your vehicle.

Answer 4

If your vehicle has high miles, you may want to consider replacing the Oxygen Sensor. This component is responsibly for delivering exhaust information to your vehicle's computer system.

The O2 sensor sends an electric signal directly in proportion to the oxygen content in your vehicle's exhaust stream. Through this information the computer can decide whether to introduce more or less fuel into the combustion chamber.

This component is always located somewhere along the exhaust path, before the catalytic converter. Newer vehicles will have an oxygen sensor after the catalytic converter as well as before. In this case both sensors will need to be properly operating.

A gasoline engine burns gasoline in the presence of oxygen. It turns out that there is a particular ratio of air and gasoline that is "perfect," and that ratio is 14.7:1 (different fuels have different perfect ratios -- the ratio depends on the amount of hydrogen and carbon found in a given amount of fuel). If there is less air than this perfect ratio, then there will be fuel left over after combustion. This is called a rich mixture. Rich mixtures are bad because the unburned fuel creates pollution and USES UP MORE GASOLINE! If there is more air than this perfect ratio, then there is excess oxygen. This is called a lean mixture. A lean mixture tends to produce more nitrogen-oxide pollutants, and, in some cases, it can cause poor performance and even engine damage.

When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. Your car performs poorly and typically uses more fuel than it needs.

A State certified smog check repair center can inspect your vehicle's oxygen sensor for proper operation, for a minimal fee.

Answer 5

No one seems to have addressed the problem accurately. Your car is supposed to consume less than half of that so a fuel leak must be suspected somewhere, probably between the tank and the engine bay. It could be an injector problem too. Whatever, this seems a potentially dangerous problem and one you should have checked out straight away. Get to your nearest garage immediately since sitting at lights with petrol dripping underneath is not a healthy way to live.

Answer 6

Also depends on where you're driving. If you're doing a lot more sitting in traffic and town driving, your consumption will go up. If you're carrying a load or a roof rack, this will also mean the car has to work harder. Lowering your speed can also save loads of fuel - e.g. sticking to 70 on motorways rather than 80.

Answer 7

its hard to know without seeing it, some suggestions may be correct, another couple i can think of is...

Your tick over may have your car running too 'rich' this is where the fuel/air mix is too heavy on fuel and doing this you burn more fuel... this is noticable if you can smell the fumes more than before...

dont forget your driving speed and conditions can also affect fuel consumption... have you been driving faster? carrying more weight (eg. extra passengers?)

i wouldn't moan too much though, 30 odd miles to the gallon is pretty good considering my jaguar uses 17 to the gallon (but it does cost me 80 quid to fill it up)

i'd agree with the other person and also look at the increase in fuel costs recently.

Answer 8

You should have your vehicle tuned up by changing the spark plugs, plug wires, distributor cap and rotor, (if equipped) Change the filters, petrol, air, etc. Check your tire pressure, and have your exhaust checked by a competent exhaust shop. This should help out the old fuel mileage.

Answer 9

If it happened suddenly, I suspect that the injectors, one or more, is dumping fuel, or you have a leak in the petrol hose (line) from tank. It could be anywhere.
Prolly a garage is the best option if you can afford it.

Answer 10

Apart from other things the cold weather effects fuel consumption most cars use more fuel during winter months....