Are you paying more than you need to for petrol?

It’s a petrol price war! Christmas has come early for motorists as first Tesco and Asda cut the price at the pumps, only to be followed by Sainsbury’s.

The price of a litre of petrol fell by 2-3p at these supermarkets, giving drivers a little breathing space.

However, the average cost of unleaded petrol has still risen from 133.3p in January this year, to 136.5p by October (hitting a high of 141.9p in April). And this time four years ago, a litre cost closer to 90p, according to PetrolPrices.com.

So while fuel may be a bit cheaper, it’s still far pricier than it was. But are you overpaying by even more? Here’s how to check.

Find the cheapest fuel

There are huge fluctuations in the price of petrol, even between different garages belonging to the same supermarkets.

In my small town, the highest price for a litre of unleaded is 144.9p, while the lowest is 131.7p. That’s a difference of 13.2p a litre!

The simplest way to find out if you’re overpaying for petrol or diesel is to compare prices in your area using the website Petrolprices.com.

Its users save an average of £2 per fill-up by checking for the cheapest prices and receiving alerts when the cost changes.

Become a more efficient driver

Last year, I set out to improve my driving efficiency and ended up saving around £70 a year.

But I only do a few miles a week as I work from home; Shell reckons the average motorist could save £500 a year by learning to drive more efficiently.

There are loads of ways to increase your fuel efficiency. For example, if you’re waiting in stationary traffic for more than a minute or two, turn off your engine if it’s safe to do so. Modern cars waste almost no fuel when they’re restarted, so you won’t burn any extra turning it off and on.

Speeding can cost even more than a potential ticket, as it uses more fuel. According to the Energy Saving Trust, driving at 85mph uses around 25% more fuel to cover the same distance than driving at 70mph.

You should also move into a higher gear as soon as possible, as this uses less fuel. Driving smoothly and decelerating early burns far less petrol than accelerating and then braking.

It’s also worth thinking about how much it costs to defrost your car by running the engine, rather than scraping. Analysis by Direct Line Car Insurance has suggested that motorists will waste a total of almost £50 million in fuel this winter by leaving their engines running for an average of three minutes a day.

Make sure your car is running efficiently

You might be an incredibly efficient driver, but if your vehicle isn’t up to scratch then you’ll still be burning unnecessary fuel.

If you’re in the market for a new car then read up on each model’s fuel efficiency when you’re assessing it. But you can also ensure your existing car is running to its full potential.

Make sure your car is serviced regularly, so that its fluids are topped up and the engine is operating at full efficiency.

Check your tyre pressure often and make sure they are filled to the level recommended by the manufacturer.

Remove any unused roof boxes or racks, as these increase the drag on your car. It’s also a good idea to empty the boot of any unnecessary weight, this means your car has to work harder accelerating (as well as slower braking).

Write to your MP

Did you know there’s a planned hike in fuel duty of 3p in January? That’s going to place a real strain on any driver who’s struggling to budget for their commute.

There had been a planned 3p rise in August, but the Government scrapped it after coming under pressure from motoring groups.

If you’d like to see the same thing happen this time round, why not email your MP and tell them how the hike will hurt you?

You can see exactly how much tax you already pay on your fuel using the PetrolPrices.com calculator. According to the Institute of Economic Affairs, tax comprises around 60% of the cost of a litre of petrol or diesel.

Make your views known now, though, ahead of George Osborne’s 2012 Autumn Statement next week.