Toyota HiLux 2014: Engine rattle

At 21,107 km, 17 days out of its 3-year factory warranty an injector rattle started in my 2014 Toyota HiLux. Toyota replaced one injector out of good will at 24,116 km; the others were within specs. The rattle is now much worse when the engine is cold and under load. I complained to Toyota, but was told there was nothing more they would or could do. With the new injector and others within specs I was expecting there to be virtually no noise. Am I correct, or is it wishful thinking?