I have a 56 plate vRS 2.0PD. Once upon a time I used to be able to get high 40s (46/47) if I sat on the motorway at a steady 60-70mph. Over the last few months something has stopped this though. I am now lucky to get mid 40s....and thats really trying, solid 60mph on the motorways being really anal. I just cant get it anywhere near 46mpg. Now i am sure something is causing this but there are a number of possibilities.

I had the car remapped about 5-6 weeks ago.

I have had a couple of dead batteries/battery being disconnected, followed by a week of driving round town before said long motorway journies.

My DPF sensor/exhaust sensor has been coming on for a week or so then going off via reset/its own accord.

Could any for these account for such poor fuel economy?

Get a scan for fault codes relating to the DPF.

I do believe DPF sensor issues can be related to bad MPG. Who did the remap?

A poor map may have caused part of the problem or made an existing one worse.

If it was Ben @ Shark he usually would be spot on about this AFAIK.

It was Ben that did it, but i struggle to see him making a mess of it. Still drives like a beauty (makes me grin to thinking of it) and as far as i can tell, no loss in power....still pulls like a locomotive!

Definitely is something up though! Will try and get it scanned at the garage tomorrow and see what they say! :(