There is no fuel injector reset button on a Ford Ka (or virtually any modern car). Fuel injectors are controlled by the car's Engine Control Unit (ECU), a sophisticated computer. Any issues with fuel injectors require diagnostic tools and often professional attention, not a simple button press.
If you're experiencing problems with your Ford Ka's engine, such as rough running or stalling, you should take it to a qualified mechanic for diagnosis and repair. Don't attempt to "reset" the injectors yourself; you could cause further damage.
