Dodgy Fuel

[hornmeister]

So I filled up yesterday from my local Esso. Super unleaded for the git as usual. It's been a bit sluggish since. Nothing major, just seems a bit unresponsive. Dodgy fuel or something else? It's usually urban trips only but I'm tempted to take it for a burn up the motorway to see if there's any cobwebs that need blowing out.
GTI with 1400 miles on the clock no other symptoms or warning lights.

Anyone got any ideas?

[hornmeister]

Seems better this morning, but is running 1/2 - 1 mpg more thirsty.

I reckon they've put standard petrol in the super unleaded pump and the sluggishness was the engine changing it's timing to compensate.

[ukmarine1]

Seems better this morning, but is running 1/2 - 1 mpg more thirsty.

I reckon they've put standard petrol in the super unleaded pump and the sluggishness was the engine changing it's timing to compensate.

changing its own timing eh?

[aaronon]

Is super unleaded better for your car? Do you think it's worth switching from unleaded to superunleaded

[Garfy]

I have tried super unleaded and quite frankly it's all hype. I achieved about 1 to 2 mpg improvement and could not tell any difference in performance.

After 5 tanks of super I've switched back to the standard stuff

[hornmeister]

Seems better this morning, but is running 1/2 - 1 mpg more thirsty.

I reckon they've put standard petrol in the super unleaded pump and the sluggishness was the engine changing it's timing to compensate.

changing its own timing eh?

I'm not an expert and I've probably used the wrong terms, but my understanding is that there are knock sensors in the engine that adjust the settings to take advantage of higher octane fuels. That's why it's recommended on the back of the petrol flap to use 98 rather than 95 ron fuel. You do need a car that's tuned for it however to take advantage. What model do you have?

The tank was on just under a quarter when I filled up and after 5 miles and on the next day it just ran rough for a couple of journeys. I've since done a bit of research on other forums and my theory seems to have some precedent.

Super unleaded is reccomended for the GTI by VW. I did see an imporvement in performance, it ran smoother, throttle response seems a touch sharper and fuel economy increased when I started using it. Of cources it might just be a me making it up, but for the small amount extra £ considering my low mileage and my plan to keep the car for many years, I'm goign to use it whenever possible.

[ukmarine1]

Hi there i meant nothing by it i was just wondering to what extent the cpu learns? last time i was banned for having the discussion on fuel lol