I never thought about the fuel tank, but interestingly I fuelled up to full and the car was very good for two days, but once it got to just above half it started to splutter even harder, that might be it, I'll have to check my tank to see if its full of crap soon, but for now I will clean my AFM, if I can't find whats wrong then eventually yeah I will just have to replace all sensors one by one, let me know if you eventually cure the problem even if its not in the near future!