Check Injector For Normal Operation

WARNING: This page is about a different car, the 2021 Hyundai Kona. However, it is still accessible from the selected car via links, so may be relevant.

Start engine.
Check that RPM is dropped when performing the injector "Actuation Test".
NOTE: The purpose of this test is to determine if there is a fault in fuel injection. Start this test in stable idle to get an accurate result.

Courtesy of HYUNDAI MOTOR AMERICA

Courtesy of HYUNDAI MOTOR AMERICA
Is there any cylinder with no change in RPM or only a small change in RPM?
YES
- Check injector for contamination, deterioration, or damage. Substitute with a known-good injector and check for proper operation. If the problem is corrected, replace injector and then go to "VERIFICATION OF VEHICLE REPAIR " procedure
NO
- Go to next step.