The fuel may be the same fuel supplied to 'all' at the refinery, but the additive pack makes all the difference.
The last 2 vehicles that I have worn out both did over 400,000 miles and were still running perfectly when I gave them away. Neither of them had any work done on the injectors or pumps in the time I owned them.
Both were owned from new and completed the mileage in approximately 8 years. ( I personally completed the mileage in both vehicles).
Both were run exclusively on Texaco fuel as I was aware as a high mileage user, that Texaco fuel gave me around 10% more miles per gallon than Tesco fuel I had previously been using. Also the car seemed to run easier, or have more power on the Texaco fuel compared to Tesco's (result of additive).
On the other side of the coin the cost of the Texaco fuel was slightly higher, but by only a couple of pence.
Must admit I find it hard to believe that the average low mileage driver would notice much difference. But I usually did 300+ miles per day over the eight year period.
It's absolutely pointless saying " I fill up at the same pump every time" and "I know my car".
The only person who can say there is a real difference, is the very high mileage user who can give more precise figures due to the higher volume of fuel being used.
I'm with EDDIE on this one ... the difference is entirely down to the additive that each retailer adds ... or doesn't.
Personally I have now gone back to Morrison's fuel as the local Texaco garage has now long gone ... along with my enthusiasm to drive more than 2000 miles a week.