Ask Honest John

Most recently answered poor fuel consumption questions
I have a 2014 Porsche Macan 3.0-litre diesel, bought new. It recorded 42mpg or better on a long run and 39mpg average on short urban runs. Porsche wrote asking for the car to have a software update for...
BMW quote up to 148mpg, battery mileage up to 25 miles for my BMW 330e. I can only attain 58 mpg and battery range between 6.8 and 12 miles. I feel I have been misled badly by BMW. I would value your opinion...
My 2016 Toyota Yaris diesel fuel consumption meter indicates a large increase in consumption for about 25 minutes every 350-400 miles. Is this the DPF regenerating?
My SEAT had the "fix", which has ruined the performance and fuel consumption and will likely lead to EGR failure in the future. Can I reset it by disconnecting the battery? Slim hope, I know.
I've had the emissions fix done on my SEAT Leon and now the car is a dog. Can Volkswagen reinstate the old engine remap and remove the flow obstructer from the inlet? The car is doing 15 per cent less...
I've found a 2002 Subaru Impreza II WRX 2.0, 110,000 miles, fitted with the Prodrive Performance Pack (ECU reprogramming, downpipe, exhaust). Will this be a reliable engine? From the looks of it, it's...
Has anybody else had a reduction in their fuel economy following the recent emissions upgrade? The range on my Audi A4 has gone from 620 to 570 miles per tank. Audi say it's nothing to do with the upgrade,...
Since taking my 2011 Volkswagen Caddy Maxi 1.6 in for the emissions update I've noticed a marked increase in fuel consumption (down from 48-50+ to 36-38) and poor performance below 2000rpm in third, fourth...
I bought a brand new diesel Volkswagen Golf in January. There was a series of minor problems at first; tyres at the wrong pressure, pulling left, a burning smell next to the front passenger wheel arch,...
I've just taken my Audi A6 in to have the emissions fix because Audi insisted that the performance, fuel consumption and CO2 emission will not be adversely affected. I instantly noticed driving back home...
 

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