Is it more fuel efficient to leave your car running or shut it off?

A car has to be fuel efficient. It means it has to completely burn the fuel.

Leaving it running burns more gas. Today's electronic fuel injection systems are much more efficient and do not flood the cylinder with gas until needed. Older motors, with carburetors, may burn excess gas at startup. That's where the idea comes from that it's better to leave it running.

Lighter weight, more aerodynamic, and more fuel efficient engines, transmissions, and tires.

It will use more fuel if you remove the catalytic converter.

The diesel engine is generally more reliable, has more power, and more fuel efficient. The diesel engine is generally more reliable, has more power, and more fuel efficient.

There hasn't really been a brand of semi trucks recognized as the most fuel efficient. Since they run on diesel a more efficient fuel, semi trucks already are more fuel efficient than cars in terms of size and power.

No, it is less fuel efficient.

Driving with the windows down and AC off at lower speeds is more fuel efficient. At higher speeds(45+), having the windows down will create more drag and it is more efficient to have the windows up with the AC on.

Electric pumps are more efficient pushing versus pulling and the fuel cools the pump. Electric pumps are more efficient pushing versus pulling and the fuel cools the pump.

When it comes to fuel efficient and luxury cars the best bet is to compare hybrid-engine designs. More and more luxury car companies are now coming out with fuel efficient hybrid-engine designs.

A manual transmission civic is more fuel efficient than an automatic transmission. That goes for just about any car.

Our school is in need of a heating system that is more fuel-efficient than the current system. or Our school needs a heating system more fuel-efficient than the current one.

Yes a diesel pickup truck will be more fuel efficient than those that run on normal fuel. Diesel is designed to run longer than the regular fuel however it comes at a higher cost.

Any car that is labeled as a "hybrid" is going to be more fuel efficient. Some of the most fuel-efficient cars of 2011 are the Nissan Leaf, the Telsa Roadster, the Chevrolet Volt, the Smart car, the Toyota Prius, and the Honda Civic Hybrid.

It's a more efficient fuel.

A fuel efficient SUV is probably better- not only does saving fuel save the Earth, it also helps you save money. On the other hand, standard SUVs may be cheaper, and making fuel efficient vehicles can sometimes use more energy than normal vehicles. In the end, it's still probably better to go fuel-efficient.

because they have got more comfortable, powerful, fuel-efficient, and more safe.

The more aerodynamic, sleek and light it is the more efficient it will be.

Driving faster uses more fuel for two reasons. First your engine is running at higher revolutions per minute, which uses more fuel. Second your car is encountering more air resistance the faster you go, which means your engine has to work harder and consume more fuel. Typically vehicles are most fuel efficient when well maintained and traveling at 45MPH, anything beyond that and air resistance multiplies exponentially.

They are fuel efficient.

a jet engine that has a propeller which makes is slower but more fuel efficient

there is no accesory for that

The Mazda Miata is very fuel efficent.

TurboCharger... Because you can control your RPM levels to prevent boost, while on a supercharger, boost is always present. On the other hand, at full boost Superchargers are more fuel efficient.

Diesel engine... you can create much higher initial compressions and much more efficient combustions because of it, with diesel engines.