Hi ive recently had a set of plugs a new airfilter and a software update on my vrs and the mpg seems to be a little worse. I would expected it to have been better as the old plugs and filter had done 29k.

Any thoughts im only thinking its drawing in more air now hence using more fuel.

Doubtfull if you have the correct filter in, the ECU sorts out the Air/Fuel mixture just fine.

A fresh new filter will normally have it breathing better and running more efficiently, that does not mean drinking more fuel.

 

Is it the change in weather thats made a difference, heated screen and mirrors and lights on more.?

Taking longer to warm up at the start of journeys, and short journeys in colder weather.

 

The ECU update could be responsible though for a change for the worse on fuel consumption.

 

Did you have the car last winter?

& Have you checked and reset your tyre pressures recently?

Yeah your right could be the ecu update or the weather.

Ive only had the car 3 months and the tyre pressures are spot on checked weekly.

On the motorway mpg hasnt gone down that much but round town it has early gone down to 30`s. On the motorway driving around 70 still doing 42 mpg on a 18 mile run.

I might not even get 25 miles from a gallon when only doing a few miles each trip around town,

oil never up to temperature before about 10 miles.

In really cold weather nearer 20 miles covered before the oil gets to 80*oC

So i guess its not too bad then just seems different than before. Cheers

If the garage did an oil change on fixed service interval then there is a good chance they used plain old quantum platinum 502.00 oil which is 5w/40 instead of longlife III 504.00 spec oil which is 5w/30 grade. The difference is about 3% worse fuel consumption.

 

An ecu software update can sometimes reset the trim values and it will take maybe hundreds of miles to relearn and retrim.

Edited 4 January, 201412 yr by xman

Have you tried both in a Twincharger and found that to be accurate.?

You do notice an indicated change in oil temperature with both the Quantum 5w 30 & 5w 40 compared to good oil.

& that might show a bit in fuel consumption, it did not as i have tried the rubbish oil Skoda Workshops use

on the journey home.

 

I let them put it in, then Drain it and replace with nice oil of a known quality.

(& use the stuff they put in, in engines that are happy with any oil)

 

I suspect the Invoice will show 'Long Life III', as being used,

even though the Twincharger is unlikely to be on Variable Servicing and require the VW 504 00

 

You can decide to boot it a couple or more times on a journey and easily cut your MPG by 50%.

Noticing what in effect is a 3 MPG drop over 100 miles is hard to spot, unless as anal as me, and doing very similar trips.

Xman no oil change i got the plugs and filter done before the schedule. As George and yourself have stated prob just the ecu update and the learning again. I do about 300 miles a week so i ll give it a chance.

Mick do you run on 99 ron fuel, V Power or Tesco Momentum or some other?.

 

worth every penny IMO,

the Momentum even more so at 5 pence a litre less.

I would pay 5 pence a litre more to use it rather than the Shell, so not just me being a tight Scots person..

V power nitro. Ive tried the momentum for around 4 or 5 tank fulls. My vrs seems to run better on the v power so ive stuck to that.