For the last couple of months my mpg has dropped from averaging 41-42mpg to 31-33mpg. I'm using the same Super Unleaded (Tesco Momentum usually) fuel as I have always used but the mpg is just hardly moving at all. I have hit a record 61mpg before now on a long run out averaging 60mph but even in town driving 30mph etc I used to hit 39mpg lowest! Any ideas what can be causing this? My driving style hasn't changed and I drive carefully the majority of the time to reserve fuel.

Any help much appreciated

Bellster

Winter really doesn't help fuel economy of any car.

Yeah I was thinking if its down to the cold weather months too. I only drive 5k miles a year but the mpg has normally been nothing short of exceptional for such a quick car.

During the cold weather is your AVG mpg showing around 25-30 mpg for the first 5-10 miles?

that would be normal.

Longer to warm the engine up and less time getting your usual mpg on a trip,

Have you reset your tyre pressures now that the weather is colder?

They might be a bit low.

http://www.michelin.co.uk/tyres/learn-share/care-guide/cold-weather-tips

george

Think it must be the time of year, just filled up and average for the last tank was 43mpg in my monte, that was a mixture of town (majority) , out of town driving. Though the turbo does seem to enjoy the colder air

Thanks George. Will do tyre pressure in the morning.

Your car may also benefit from a good clearout too! If you have been driving very steady for the last month or two the engine will be collecting a certain amount of dirt inside on the valves, plugs, and chambers. The ports and injectors won't be quite as clean either. Engines like these have to be driven like they were designed to be driven quite often. These are quite a clean running engine when driven quite hard but they don't actually like being driven slowly or without stress for too long. They suffer and clog up hitting mpgs and performance too, and as George is implying, the cold weather makes it worse as the fuelling stays rich for much much longer making the engine much dirtier over time.

It been very cold today and the car has sat for 5 days without moving so i took it out for a wee run.

33 miles in freezing fog patches & some light snow flurries, so only going at around 50 mph and the oil never got near up to temperature.

(used a bit more fuel coming home on a different sunny road and it warmed up nicely.)

Just love this car & its possible economy.

george

It been very cold today and the car has sat for 5 days without moving so i took it out for a wee run.

33 miles in freezing fog patches & some light snow flurries, so only going at around 50 mph and the oil never got near up to temperature.

(used a bit more fuel coming home on a different sunny road and it warmed up nicely.)

Just love this car & its possible economy.

george

George how is it possible for you to achieve those figures? Are you dirving with an egg under the throttle?

Im having a hard time to achiving anything above 45-47mpg on a long drive..

I get 45 mpg now regularly on long runs.

It used to be nearer 50 - 55 when trying just to see what it could do.

george

http://www.briskoda....in-a-vrs-45-mpg

Well best I have managed is 35.4mpg which compared to my usual average 43mpg on the same run is terrible. Tyre pressures checked and correct. Winter weather can't surely cause a lose of 8-10mpg can it? Could I have a dodgy air filter perhaps? All this started after my service. There is a slight noise when the heater is on 2 as well which was never there before either. Its driving me mad!!

I would say it can easily be that much worse for consumption.

I have had my lights on all the time, and lots of A/C or heater demisting or heating.

In the last 1000 miles i have used petrol at around the same rate as you.

just between 35-40 mpg

So that is down 8-10 mpg on my usual on long runs for most of 2012.

750 miles in 5 days of only long runs, but some nippy driving and always cold starts at around 0 C*.

Have a look in the Air Filter housing and see how the filter looks.

I would say that you are getting what the majority of vRS drivers achieve

& pretty good MPG in warm weather.

? How many miles on the clock?

george

Hi George. Currently 14142 on the clock and its 2 years old.

Hopefully at its best from now on & you will be back up in MPG when the weather warms..

(looks like winter here from next week.)

I had to fill up and instead of just putting in enough to get to a Tesco i brimmed it with Sainsburys Super.

Just done over 400 miles & still showing 60 miles to go, so back to around the 45 MPG.

So easy to drop in Average MPG with cold, wet, wind or weight with a vRS.

george

That's the one thing I don't really do (and perhaps I should be doing) and that's filling to the brim. I put £35 worth in today and got a reading of 270 miles unsure if that's accurate or not? I tend to full 3/4 of the tank and let it run down until the warning light beeps and I fill again.

The 270 miles is showing on the AVG when you filled up,

so depends on if it was at the likes of 30 mpg or 40 mpg at the filling station.

george

George just done aired accurate tyre pressure reading using my dads all singing all dancing digital reader and both the front and back were very low indeed! 22psi at the front and 24 at the back! Couldn't believe it. Anyway pumped up the front to 36psi and the back at 35psi. Hopefully I will see a slight improvement over the next few days/weeks.

Meant a more not aired!

George just done aired accurate tyre pressure reading using my dads all singing all dancing digital reader and both the front and back were very low indeed! 22psi at the front and 24 at the back! Couldn't believe it. Anyway pumped up the front to 36psi and the back at 35psi. Hopefully I will see a slight improvement over the next few days/weeks.

So the tyre pressure warning system is not working/set.

Pressures that far out were very illegal.

I would check out the tyre pressure warning system.

The handling should be considerably better with the correct pressures.

Regards

Tony

If the tyre pressures just reduce kind of evenly there is no way for the TPMS to warn of that.

It should warn of a sudden change in pressure or diameter of the tyre, best use with run flats.

The TPMS is not a replacement for regular tyre pressure checks and then checking or at least re-setting the system.

george

I have had no warning lights or anything to identify pressure loss in any of the tyres. To be honest in the 12 months I have owned the car I don't even know about tyre pressure system on the car or how to set it up if it hasn't already been. I'll have a look at that and consult the manual

The tyre pressure warning system detects if one tyre suddenly develops a lower pressure than all the others. If all 4 have been slowly losing pressure at roughly the same rate it won't pick this up.

'Sudden increase in MPG'.

This was not going downhill or after hypermiling, 70 mph after messing about a bit then steady driving @ 70 for about 10 miles as the oil cooled.

New ECU with REVO Stage 1 installed.

Standard Air Intake, box & filter, 205/40 R 17 tyres but cold ambient Temp.

(just comparing things, it could go bang very easily and not in a good way.)

I will see how much fuel i actually go through with a few tankfulls.

Before & after.

My vRS is booked in to the dealers on Monday for engine diagnosis regarding my loss in mpg. Just so I know what to have checked can anybody let me know what to make the dealer aware of to check off so that all possible avenues have been checked:

Air filter

O2 sensor

General engine diagnostic check

Breather pipe

Anything else specific I should be asking to have checked? I'm not mechanically minded so just want to be prepared.

I still can't get better than 28mpg at the moment ad that's without lights/heater/wipers on etc

Cheers

I think they will be plugging in & checking for codes, and then checking the spark plugs.

Are you doing runs over 10 miles,

coolant up to temp and oil temp showing at 50oC and above and it is showing only 28 mpg.?

george