Some tips on saving money on fuel are out of gas. Here’s what to know

Rising gas prices have everyone scrambling to find ways to save at the pump and conserve fuel.

But some tips and pieces of conventional wisdom won’t do you any good and a few may actually worsen your gas mileage or damage your vehicle.

Some are simply outdated, while others are just nonsense, said experts.

Here are some tips that actually work.

Here’s what you need to know about the ones that don’t:

Myth: Turn your air conditioner off to save on gas

Vehicle air-conditioners are gas-guzzlers, but driving with your windows open to cool down instead creates problems of its own, Sustainable America said.

Lowering your windows on the freeway hurts your vehicle’s aerodynamics and increases drag that can offset any savings from turning the air conditioning to “off.”

Myth: Keep your tank full to prevent evaporation

Topping off your tank to prevent evaporation is “bunk,” CNET said. Modern vehicles are equipped with vapor recovery systems.

Myth: Leave your vehicle running to conserve fuel

Modern engines with fuel injectors simply don’t need that much gas to restart, meaning the old guidance that it’s better to let the vehicle idle instead no longer holds true as long as it’s only for a short time, Sustainable America said.

Your vehicle doesn’t need to warm up in the mornings anymore either, Auto Care Plus said.

Myth: Put your vehicle in neutral

Putting your vehicle in neutral when you’re stopped, such as at a red light, doesn’t save gas, Motor World Honda said. Modern fuel injectors ease off when you take your foot off the gas anyway, so shifting to neutral doesn’t do anything.

Myth: Buy gas early in the morning

The theory goes that gasoline is denser in cooler temperatures, so you can get more for your money by filling up before it gets hot, CNET said.

But gas stations store fuel in climate-controlled underground tanks.

Myth: Premium gas always gets better mileage

Most vehicles are designed to run just fine on regular grades of gasoline, Sustainable America said. Check your owner’s manual — unless your vehicle requires higher grades of fuel, save your money.

Myth: Replace your air filter frequently to save gas

Older vehicles had carburetors, so a clogged air filter could hurt your mileage. That’s not the case with modern vehicles, CNET said. Of course, dirty air filters can cause other issues.

Myth: Manual transmissions get the best mileage

While manual transmissions outperformed older automatic transmissions with fewer gears, this is another case of technology turning outdated conventional wisdom on its head, Sustainable America said.

Nowadays, the make and model of your vehicle means more of a difference than the type of transmission in it.

Myth: Buy fuel additives

The Federal Trade Commission found that most fuel additives don’t do anything to boost gas mileage. And gadgets promising to save fuel can actually damage your engine, CNET said.

Myth: Hybrids only save fuel in city driving

While it’s true that hybrids conserve the most fuel in stop-and-go city driving, they still stack up pretty well against traditional vehicles when it comes to highway mileage, Sustainable America said.

Myth: Overinflate your tires to save gas

The theory behind this myth is that reducing contact with the road will reduce drag and conserve fuel, CNET said. But all it really does is reduce traction, increase wear and cause the vehicle to take longer to brake.