In all the years I have driven my Freelander it has consistently returned an average 32.7mpg, according to the on-board display. A few weeks ago it began to run cool; thermostat knackered. As I posted earlier I replaced the thermostat, and while I was at it I fitted an EGR blanking plate. Now here's what I found:-
January: A 1,000 mile round trip from Argyll to the west country via the home counties. The usual mixed back of 'A' roads, motorways, roadworks and town driving. That's two tanks of fuel; the first one premium diesel, the second one the cheapest. Average MPG 32.7
March: The same journey, but with a u/s thermostat. Same mix of premium then ordinary fuel. Average MPG 31.
May: Here we go again. Same journey with new thermostat and EGR blanking plate fitted. Now here's the difference. With the first tank of premium fuel I averaged 37.2 mpg, something I have never achieved except on interminably long stretches of 60mph roads with average speed cameras. On the return trip with a tank full of the cheaper stuff the average MPG slowly fell back to 35.5mpg.
To be honest I didn't notice any change in handling, hill climbing or throttle response. Even by sticking the car into sports mode and driving it like I stole it I struggle to get the MPG down to pre-EGR blanking levels.
Now, I don't expect the on-board MPG figure to be accurate, but I do expect it to be repeatable. Running on premium fuel does look as though it gives improved MPG, but not quite enough to compensate for the price hike. I'll probably continue to use it on long journeys and in the run up to the MOT.
Conclusion? I should have blanked off the EGR years ago.
And a big thank you to the people who contributed to this thread who persuaded me to give it a go.
P.S. The engine warning light has not come on, though there is an OBD fault code indicating an EGR valve problem.