Fuel Injectors

There is really no way of telling unless you have a fuel injector tester or remove the fuel rail connect the injectors and look for a cone shape pattern.

Check this guide out.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

You'll end up burning more fuel to keep it going-imbalance air/fuel mixture to the cylinders

Get all the injectors serviced & flow tested, do not just do the one faulty injector, you wiill pay for this quickly with the saving in fuel usage.

Check spark on the cylinder if it is known which one. Do a compression test on the cylinder. Listen to the injector with a long rod or screwdriver for a clicking noise. If you verify spark and compression on the cylinder, it can most likely be the injector.

The color is not the important issue. They could be from different suppliers or different manufacturing dates. What is important is their flow rates. Replacing just one or two injectors can result in them having different flow rates. That has been the source of a lot of Check Engine light problems on 1990's GM vehicles. At high mileage, one or two injectors flow a lower fuel volume resulting in some cylinders running lean. There can be misfires too, so you are chasing misfire fault codes and "running too lean" fault codes. The fix is to buy a flow-matched set of rebuilt injectors. Most manufacturers buy their injectors in flow-matched sets from their suppliers. GM is one of the few that just grab a handful of injectors out of a bin and toss them into the engine with no regard to flow-matching. That does not cause a problem until they have a little wear from high mileage, then the elusive problems start.

Your car is not new enough to have the computer controls that detect misfires, and those that might occur are generally too hard to notice.