Bore wash happens if car is mapped incorrectly, you don't happen to run grey injectors by any chance do you as some tuners map these incorrectly? However this won't be your problem as injector number 2 is constantly open by sounds of it, I presume it was sudden as you would notice this. Check the earth wire from the injector to see if it's chaffed on where it goes (through the bulkhead for example) to the ecu. Loss of compression could be a gasket hopefully not the HG or worn valve seats.

Martin