So it turns out using 95 RON Fuel caused all my false readings for the ITV/MOT here in Europe. As crazy as it seems, it turns out that 2/3 tanks of 98 RON fixed the error and the idle and stationary acceleration checks all passed with the 98 RON fuel.

Apparently the oxygen sensors get a bit screwed up and whilst it doesnt get any damage to the car it causes them to put too much fuel through as they dont work correctly on 95.

 

Agreed,
Your 95 RON is equivalent to our 91 octane, therefore 98 RON is equivalent to our 93, I never put anything lower than 93 or 94 in my vehicles.

Johnny

 

I remember when they called it "Hi-Test." Instead of paying 29 cents a gallon it was 34 cents. Multiply by 10 for today's price!

 

98RON or 93AKI is a minimum I'd recommend for pretty much any modern turbocharged or atmospheric high performance engine. The adaptive features in ECU adjust timing advance according to indicated knock incidents and you'll get far fewer of them with a higher octane fuel. At one point we had a bunch of lab tests done with different brands of "98 octane" and it turned out two of them were above 100RON and 95AKI at the time. We used this information to our advantage in a tightly sanctioned racing series and had a power and torque advantage over the competition.

My Spur and my wife's RS6 seem to be the happiest when fed Aral 102RON on trips to continental Europe. I wouldn't imagine filling either of them with 95RON, at all.

 

Just really surprised it made such a difference to the car component readings or lack off, but all good now its back on 98 all the time!!

I wasn't doing it for any real reason other than being a bit lazy but tbh I have hardly used the car with it being in the dealers for so long but now I will.

Will not make the same mistake!!