Filled my 1993 Golf 1.8 mono-motronic (AAM) engine with BP ultimate, and after about 10 miles the car started to run really badly!! When I take my foot off the accelerator, just as it settles back at idle speed, it starts to shudder and vibrate quite badly, same when accelerating back up again.
When driving though its drives like normal, no improvment. I'm worried though about the shuddering, as its worse when cold. On my model theres no 'check engine' light, so i dont know if theres a fault being registered, and I dont want to pay 60 quid to have vw 'just check' it!!
Once this tank has finished, I'm straight back to normal unleaded!!
I had the exact same problem whilst using optimax but after a while of using normal fuel the car start shuddering again. I've had my fuel pump changed and the car is better but I'm far too scared to try optimax as that shuddering is REALLY scary
