On the drive to work this morning the istant mpg read out was going from mid 20's to low 50's and back down to mid 20's with the cruise set at 70 mph, it usually stays around high 30's low 40's. The morning before i had 40's - 50's

Anyone have any ideas where to look or what to log with VCDS.

Outside temperature will influence mpg and fuel brand

My cruise control often does that as it comes on and off dependant on the slope of the road, when it gets up to speed, etc.

I assume this is why people say cruise is slightly less economical than keeping a steady speed yourself - it's on/off rather than smooth

Heavy winds at the moment. Maybe you were driving into wind.

It not the road or cruise Causing it as I've been doing the same run for months. It like I'm driving up n down a hilly road that's how fast it goes up and down. I've done 150 miles on half a tank and it says I have 155 miles left something is not right lol

300 odd miles to the tank in the Tfsi sounds about right to me?

On the drive home this morning it stayed high 30's mid 40's.

Mine did it a while back. Was like it had reset so small variations mad a big difference. Settled after a couple of hundred miles.