Isx15 2350 knock.

[SemiSweet]

Mine had a similar sound and again would do it at certain rpm even completely warmed up . It was an injector. But, the injector passed a leakdown test and performance was not compromised, the culprit injector was easily found with a cylinder cut out test. I honestly could have left it, but my OCD forked out the cash to replace it….not a change in performance, fuel mileage nothing.

If you can do a cutout test, confirm it’s an injector and it passes a leakdown, I’d say run it.