Ask Honest John

Most recently answered fuel questions
I really don't like the idea of buying an electric powered car. I have seen articles from some quite major companies who have made a hydrogen engine. Why would they go to the expense of doing that if they...
I have a 1981 motorbike and want to get it running again. It ran on 4 star petrol and 2 stroke mix. What petrol should I use now?
I have a Peugeot 107 on a 10 plate. The specified fuel for this is E5. What is the danger if I run it on E10? Bear in mind that E10 fuel did not exist when E5 was specified for this car.
Which or what type of additives should I use with lesser brand diesel fuels and how frequently?
Should I use additives in a 3.0 Jaguar F-Pace diesel, other than AdBlue?
I have heard that supermarket fuel damages the fuel injectors and its best to use non supermarket fuel - is this true?
What is the legal position on carrying in a private car a can containing spare E10 petrol? if it is legal so to do, what is the best currently available 'explosafe' can?
My local BP garage is still charging £1.55 per litre for their cheapest diesel, much more than any prices mentioned in the article (although in November 2023 it was 10p more at £1.65). Why would BP be...
A local company says it can adjust the fuel use of my Citroen C5 6 spd, 2.0 HDi, upping it 10% without risking any parts. I'm a slowish driver, mostly 2,000 rpm and have the car in eco, whatever that does....
Is it better in the long run to top up fuel at half tank on a regular basis or to refuel when almost on reserve?