Rover 420SLDi Turbo - Peter
My fuel consumption fluctuates between 57mpg to 45 mpg, the average seems to be ~54mpg. I check by filling the tank to full and doing a calculation against the miles travelled. I travel over 100 miles/day so I have monitored the situation over several weeks.

I fill the tank to full but one question I would ask, is there a possibility of an airlock during the refuelling. There is a noticeable swishing and gurgling when I drive away. Following a full refill I drove 137 miles and filled it up again, on that calculation I achieved 66mpg.

Or is there a defect in the fuel metering system, I am not familiar with diesel technology. There does not seem to be any engine fault, it runs and pulls effortlessly with no sign of engine distress.

Thanks in advance.
Rover 420SLDi Turbo - Civic8
My 218sld Turbo has done the same. Though I would expect this due to cooler air. Ie winter. Nothing wrong with engine
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Steve