It's good that you're cleaning the injectors, it can only help.
You really should replace the fuel filter if you haven't already, and check all electrical connections to the pump to be sure they are tight with good connection.
If the FI light comes on again try to get it in dealer mode while the light is still on, then you will see which code number it reads.
It sounds to me like its either ;
1) fuel pressure dropping due to a blockage, possibly clogged filter.
2) Fuel pressure dropping due to a bad electrical connection,
3) A fuel pressure regulator fault causing pressure to drop away,
4) One of the ignition coils failing when getting hot, restored when cooler.
5) A bad Ground connection somewhere in your ignition circuit. or fueling circuit.
So that's a few obvious things to check, that is where I would be looking first,
Good luck mate, let us know what you find.
