Volkswagen Repair: feul injectors, distributer cap, computer box

Question
i have a golfiii 2l 8v gti "95.i suspect that the feul injectors are faulty. how would i be able to confirm that they are faulty.the vehicle was serviced about 4000km ago.i have the old plugs and feul filter.the current millage is 225000km.the engine has not been modified.the computer box was reset/cleared off errors.the distributer cap and rotter cap has been replaced,and so has the plug leads.

Answer
should've first changed the plugs to complete the tune up, also change the fuel filter for who knows if there is water in it which won't help the running situation.  This is much cheaper than checking the injectors and that is normally done in a shop and a injector shop charges good coin.  So stop blaming the carb first(some things never change)