Tesco 99 Octane Super Unleaded

[Alpineandy]

In the early 80s shell came out with a new improved fuel - formula shell 4* (i think) which had a special formula which would clean your engine. They said it came out of their development of petrol with mclaren F1 (what bulox).
The only problem was that most cars ran badly on it (mine did and the engine didn't look any cleaner either, especially round the dip-stick)... So they took it off the market