Yea there are 'fuel injector cleaner' additives you can put in the petrol tank which you can buy from supercheap/repco etc. Brands like nulon and the like. Prehaps if you use it periodically from when the car is new they may work, but using it on your 100k+ dirty injectors wont do jack imo

Are you using 98 fuel? Try it and see what happens