Car Question - Fuel Efficiency

steven77

Hi All

I've been doing a driving experiment recently, I reset the calculators on the car and started driving to check the fuel efficiency. Parker's says I should be getting 34mpg on average, and I'm getting 19mpg! I have 1 tyre which I think has a slow puncture but I can't believe that is causing all the problems... it's not overloaded, I don't overuse the aircon... has anyone out there got any advice as to what it may be or what may be worth checking?!?!?

It's a 2 Litre Mazda 6 btw...

Hammyman

Aircon is a 10% hit. Low tyre pressure is a hit. If most of your driving is short (<5 mile) urban journeys, it'll be running on cold start most of the time. And then there is the manner of the driving. If you drive up to something then brake as opposed to coasting up off throttle, that uses more fuel.

Evilm

My hubby used to get about 20mpg on his run to work when he had to do a lot of stops and starts. Now he works straight up the A34 and does a longer run with fewer stops and is getting 25mpg or so.

Next time your service is due tell them that you are getting awful MPG on it and see if they come up with any reasons once they've checked the car over. If they can't it might just be your style of driving.

10JH

What kind of roads are you driving on? Motorways, city?

The puncture will likely be causing a fair bit of hit, but you still sound a long way off the claimed figures!

harveybobbles

Just leave the computer alone and work it out manually. Brim the tank, note the mileage, drive, fill the tank, note the mileage, work the sums out

More acurate over a long distance - ie a full tank's worth.

maninthestreet

What car is it? What size engine? Petrol or diesel?

harveybobbles

maninthestreet wrote: »

What car is it? What size engine? Petrol or diesel?

It says in the original post...

anewman

Driving at 85mph instead of 70mph will also usually decrease mpg so if you're an outside lane owner along with the BMW's anbd Mercs it might be worth slowing down I get a very noticeable increase in mpg travelling at 65mph on the speedo (about 60mph in reality) although I am sure most cars are different. Travelling at 60 instead of 70 only adds 14 minutes per 100 miles to your journey, 14 extra minutes to listen to the radio etc all while saving money on fuel.

As for things mechanically worth checking, it's all the usual service stuff really. Air filter, spark plugs, make sure the correct specification of oil is used and the oil is changed at least as often as specified.

Also as stated above mpg display in car is often not accurate and the tank brimming method of calculating mpg is best.

LandyAndy

harveybobbles wrote: »

Just leave the computer alone and work it out manually. Brim the tank, note the mileage, drive, fill the tank, note the mileage, work the sums out

More acurate over a long distance - ie a full tank's worth.

There really ought to be a sticky on this board along the lines of:

'Don't bother posting about your fuel consumption until you've measured it by the 'brim-to-brim' method'

moonrakerz

Hammyman wrote: »

Aircon is a 10% hit.

On a two litre car a/c is hardly noticeable - the biggest factor, by far, is your right foot !

anewman

moonrakerz wrote: »

On a two litre car a/c is hardly noticeable - the biggest factor, by far, is your right foot !

I doubt a heavy right foot in itself reduces overall mpg much, getting up to speed is only a very small part of the journey. Cruising in the highest appropriate gear and driving at the peak torque for the engine (instead of doing 80-90mph on the motorway) - and thrashing it to get to that speed, is likely to be still quite fuel efficient.