Thanks for holding, Larry!
The next thing to look into here will be the fuel injector for cylinder #6. With the engine running, unplug the electrical connector to the injector, the engine should respond with a worse idle. If not, inspect the electrical connector and wire harness for any loose, broken or damaged wires. If no problems are found, the injector will need to be replaced.
If the injector checks ok, next an intake air leak test should be done. With the engine running, carefully and sparingly spray some throttle cleaner around the base of the intake. If the engine responds, this is a sign of a leak and the intake gasket will need to be replaced (make sure to visual inspect the manifold itself for any cracks at this time as well).
If the intake test proves no leaks, then ultimately, a cylinder compression test will need to be done.
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