Originally Posted by Pleiades

Try the Stage 2 map and see if it's any better. If it is then I'll have a look at the fuel trims in the two maps and see if there is anything obvious. Looking at the spark plug will give you a very rough idea of what's going on with an air/fuel ratio but with modern fuel containing ethanol they are much harder and less reliable to read as the fuel additives leave odd coloured deposits even if the engine is running well.

As for the fuel light... they all do that! They are unreliable and inconsistent (the fuel gauge on a Z is even worse) and should only be ever used as very rough indicator that the fuel level is dropping. Best just to reset the trip and get used to how many Km you can go before you need to fill up.