TDI 130, MPG Concerns.

[deano-1000]

Hi everybody, first time I've used this site, just wondering if anybody could shed some light on why my passat TDI 130 mpg is going down.
I originally bought the car 3 years ago (52 plate) with 17000 on the clock, it now has 47000. It did average about 50 mpg then, some journeys even got 60, but now only get about 40-45 if really lucky and light on the pedal. It has full dealer service history which I keep up to date.
I recently changed the air filter, (was really filthy, VW didn't change it for some reason) put Millers Diesel Plus through it and even had the EGR valve off and gave it a good clean.
Is there some thing else to try or should I be lucky to even get 40 mpg?

[mluton]

It could be a faulty MAF sensor. Have a search on the site, there is plenty of infomation.

Welcome to the forum

[deano-1000]

Thanks mluton, will take a look.

[daveo138]

I recently gave mine a 120k service and couldn't believe the state of the air filter. I thought there's no way it was changed at the last service, but when I checked, I discovered that it is only changed at 40k intervals.

[Frank.A]

Our Passat only covers around 6K per year but I was amazed at the state of the air filter at its first year dealer service,which of course was not chenged as it was not scheduled.I now change the air filter and pollen filter together with oil and filter each year.The scheduled 40K figure for the air filter is longer than any other car I have owned.The filter has quite a small area for the size of engine,less than our Corsa air filter.
The health of the MAF is dependant on the cleanliness of the air supplied so why cut costs.

ATB,
Frank

[daveo138]

I agree. I would have thought that 20k was easily enough for it.

[deano-1000]

Many thanks for all your replies, I didn't know that VW say an air filter should last upto 40k, that's just daft, I've replaced it and also the MAF, mileage back upto 50+mpg.
Changed the MAF because I did a search and have found that these degrade over time and are past there best after 40-50k miles. £64+vat from a dealer.
Many thanks again.