i swore by Tesco super shyte, lived right next to a tesco station so used it for ages,

began having "air leak" symptons with my 2.2 20vT engine, running lean, EGT right up into the 700`s when cruising at 70mph etc,

went to Derby on a training course and it got so bad with EGT`s nearly 800deg C!!
while i was there we smoke tested the inlet/breather and both intercoolers etc

no problems,

Live data all fine

so thaught nothing of it, on the return journey i used Vpower, and it solved the issue!
as in the second it started up from idle at the fuel station

Would never use Tesco again, ever in any car.

Also Esso is the same stuff as Vpower if you didnt know, same mother company and supplier (it isnt actually shell.....!)