60,000 miles – average mpg 48.4 2.0TD Passat. 😛

Mainly sitting at 80mph on motorways / autoroutes.

Bit pointless saying 'blah blah blah 53 MPG' if it's on one journey. I can get my diesel to show 999 MPG if I go down hill with my foot off the gas

Not pointless at all. I told you where the journey was and how fast I did it. A long and entirely representative journey including a lot of well-travelled motorway and some A and B roads. Not at all a special case.

And I am not for a minute attempting to persuade you that I could average 53mpg over thousands of miles. If you read carefully you'll see that I mention a typical tank average of 48 ish mpg and with summer approaching I would expect that to creep up a bit…

Don't see the problem here. Except that it's a thread hijack since the original thread was about BMWs 🙂

I once worked with a guy who by his own admission 'cracked one out in the toilets everytime he had sealed a deal'.

This was London after all and no, I never shook his hand.

Banker?

Seems like the computer OUGHT to know the flow rate of its injectors and the pulse durations pretty well.. right?

Yes, they do, but speed sensor readings have a fairly low refresh rate and so are fairly inaccurate during transients, which is part of the reason that most OBCs are fairly accurate over a sustained fairly constant speed journey but less accurate in stop-start traffic. Some handle it well though, it depends whether the algorithm for calculating it was a gimmic added into the software for user viewing later on, or built in with some intent on accuracy. Things as simple as how the guy coding it decided to round the values in the calculation and how much "processor time" is allocated to gimmicks.

I'm still standing by original statement but perhaps I should have included the word average in the MPG bit.