Ask Honest John

Most recently answered performance fuels questions
Following your advice, I filled up with Super Unleaded and was slightly disappointed to find I only got an extra 20 miles out of my 40-litre tank. I have filled up a second time, this time with Shell V-Power,...
What is the best petrol for economy and performance for my Audi Q3 2.0 TFSI Quattro? Is it Shell, BP, Texaco or Esso? Should I buy a "super" petrol e.g. Shell V-Power or other suppliers equivalents?
We have a new Ford Fiesta Ecoboost 100PS, but the fuel consumption is nowhere near what the stated mpg should be. We're getting barely 42mpg which is hardly any better than our prior, 2006 Ford Focus 1.6...
My wife's 2006 Renault Clio 1.5 diesel has covered 80,000 miles and recently suffered fuel pump failure. A new fuel pump and sensor, plus reconditioned injectors have cost us about £1500. We had been hoping...
Should I use cheap supermarket petrol or better quality branded fuel?
Other than the increased octane rating, does Tesco Momentum U/L have any other advantages over their basic U/L and how does it compare with Shell Fuelsave U/L?
Assuming that BP Ultimate or Shell V-Power diesel is not readily available (I am going abroad), do you recommend the use of Millers Diesel Power Plus during the running-in period of a new Honda DTech 2.2...
After reading your glowing report of the BMW 320d ED, I have bought a one year old model. Do you think it is worthwhile using a premium fuel such as Shell's V power? Many reports on BMWs talk of traction...
I am buying a new Mazda 3 and the dealer recommends that I use normal 95 RON petrol rather than the higher octane petrol such as Shell V-Power, which I believe is 98 RRON. Would you recommend that I continue...
I usually fill up with branded diesel rather than supermarket diesel but would I get any benefit from switiching to Shell V-Power or similar? My car has done 65,000 miles. Would there be any risks involved,...