Misfire cylinder number six, will not run

Hello, I am Danny.

It sounds like you are having a problem with cylinder number six injector. The code P0206 is a code describing number six control circuit. In your post you stated you replaced that cylinder injector. Since the symptom is persistent/still there I suggest using a Noid light set to check injector pulse for that cylinder. Basically you unplug Injector harness at the Injector and the Noid light is plugged into the harness. The Noid light itself will be for GM vehicles and is clear plastic with a sight bubble. When vehicle is started and running if the harness is functional you will see a light flashing in the bubble to verify the injector signal is working. No light flash indicates a problem in the circuit and the Injector is not being fired. I can send more information and diagrams if needed when test completed. Hope this helps and feel free to ask any questions if needed.
Danny-