Hi Pete,
Your issue categorically is not due to the type of fuel, as per my previous reply. You have an intermittent fault with one of your components, and it is most likely your 2nd hand MAF sensor. As it is intermittent, it may be fine for 100's of miles, then become problematic, then fine again. This is giving you the false impression that the fuel you happen to be using during those miles is having an effect, but in fact it isn't. Air temperature, humidity or any number of factors may be having an adverse effect and causing it to malfunction now and again, as MAF's are incredibly sensitive. I hope I don't sound blunt, but I just don't want to see you wasting more money on premium fuels and additives to try and solve your problem. Hope this helps mate
