I just went through the first 30,000 km (¨20,000 mile) service with an oil change etc. During this, the car was hooked up to the Skoda IT system for any software or firmware upgrades.

The car feels a little different after this. I cannot quite get my head to accept that it might just be fesh oil, and after a few trips, It does seem that mileage has improved some - maybe one or two mpg over what it was.

My past experience is as follows:

Normal weekly runs - mixed short trips and occasionally 50 mile runs: 47 mpg.

High speed German travel: 40 mpg.

After service, test with no A/C and mixed urban/suburban 20 mile trip: 54 mpg. Keeping to speed limits all the time - almost.

After service, typical home - Copenhagen- Home run, 125 miles, 1/3rd each motorway, urban and suburban travel: 45 mpg.

The aceleration and responsiveness in general has improved - not deteriorated. The normally very quiet noiselevel seems to have been further reduced.

My thesis is that whatever developments Skoda (or VAG) made to reduce the CO2 values for the 2.0 170 HP engines for the 2011 model year were also retrofitted to the normal software for the existing vehicles. It may be a subtle change in mapping of the engine to run cleaner and more efficient. On the other hand, it may just ´be wishful thinking and the feeling that a freshly washed car with an oil change runs better.

It would be most ineresting to hear from 2.0 140 hp and 170 hp owners, as their gear ratios and final drive ratios are the same. The 105 hp has a different gearbox, so those are not directly comparable. My theory is that the 170 hp engine is as fuel efficient as the 140 hp in real use, as the pumping and frictional losses must be the same. Only if the maximum available power is used, the 170 hp uses more fuel. This fits the old time tuning experiences with petrol engines, where if you tuned the car to provide more power by making it more efficient, you also gained in economy if you did not use the extra available power.

im sure all yeti model's will benefit from these software changes, diesel and petrol alike...ive just taken delivery of my 1.2 and im getting an avg of 44.8 mpg ...and mines the new 11 model, and so will have the latest software allready...manafacturers do indeed alter software as time goes on,and of course the first yeti's are nearly 1 yr old

im sure all yeti model's will benefit from these software changes, diesel and petrol alike...ive just taken delivery of my 1.2 and im getting an avg of 44.8 mpg ...and mines the new 11 model, and so will have the latest software allready...manafacturers do indeed alter software as time goes on,and of course the first yeti's are nearly 1 yr old

Mmmm....just like a good claret, the 2009 Yeti is a very good vintage

diesel of course

Agreed