Hi All,

I've noticed recently my Octavia 1.9TDi PD on an 2005 Plates fuel consumption has dropped majorly. It used to get around 55-60mpg but now I am lucky if I get 40-45mpg.

Its done 113k now, and was last serviced in December at 105k. Its not lost any power as far as I can tell and no overly black smoke is coming from the exhaust other than on start up and when I boot it.

Any ideas what it could possibly be?

Cheers

Craig

Try changing air filter that can help. My mpg is always around 60 to 65 at the moment in this weather.

A while back I noticed a drop (rise?) in consumption and traced this to a failing Air flow meter MAF (Mass Air Flow sensor).

It's not a dear part and testing is simple: Unplug and give the car a drive. An engine check light will appear after a few miles and would require reseting.

If the car drives worse: the MAF is good. If the drive improves or stays the same, your MAf is failing. Essentialy, an unpluged MAF puts the car on a default mapping which would be worse than a good sensor but better, or the same, as a failing sensor.

In my case, the difference wasn't easy to spot, but a couple of months later, when I tried this again, the difference was clear and consumption has never been better.

HTH

You could try an injector cleaner in one or two tanks of fuel, just to see if it helps. It's not expensive, so a good way to rule that out.

Have I heard people changing their fuel filters to get a better mpg?

A blocked fuel filter usually improves mpg (but makes performance worse).

Check oil? My mpg drops when the oil gets a bit low.