Cylinder seven misfire, flashing service engine light

Good afternoon,

Can you tell the results of the compression test?

https://www.2carpros.com/articles/how-to-test-engine-compression

This could be a fuel injector. Did he check the injector and see if it is firing at idle?

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

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Roy

REMOVAL PROCEDURE

NOTE: Use care in removing the fuel injectors in order to prevent damage to the fuel injector electrical connector pins or the fuel injector nozzles. Do not immerse the fuel injector in any type of cleaner. The fuel injector is an electrical component and may be damaged by this cleaning method.

IMPORTANT:
The Denso fuel injectors that are installed on the 5.3L (L59) E85 application will not have O-rings and retaining clips serviced separately. Therefore the fuel injectors will be replaced whenever an O-ring or clip needs to be replaced.
The engine oil may be contaminated with fuel if the fuel injectors are leaking.

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1. Remove the fuel rail.
2. Remove the fuel injector retainer clip (19).
3. Remove the fuel injector (17).

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4. Discard the fuel injector retainer clip (1).
5. Remove and discard the fuel injector O-ring seals (2, 4) from the injector.

How did he check the injector?

Yes, it could be a lifter. He needs to remove the valve cover and watch the rocker arms move. If it is a lifter, you will see little movement on one rocker arm.

No to the ECM. It would code.

Roy