Unresolved Would this be a feed rate issue?

I am still on my quest for a full day of 3D printing without a filament jam, axis misalignment or some other strange goings-on. The problem I'm having now is that when I start a print all goes well for about 10 cm of filament. Then the print starts to peter out and within a few seconds no more material is extruded. There then starts a series if clicking sounds. I quickly discovered what those sounds were. Filament was continuing to be pushed through the cold end but then cannot proceed to the heatsink an on to the nozzle. It just piles up. When I clean it out and bring the extruder back up to temp I can press what seems an unlimited quantity of material by hand. My first thought was the feed rate had, for some unfathomable reason, gone out of wack (to use the technical term).
I reviewed Tom Sanlader's youtube video on feed rate calibration and took careful notes. He says to send the gcode M503 to get the extruder's current rate setting. When I do this I get the PID numbers back! I have a "cheat sheet" of gcodes but it is far from all inclusive. Is there a source of gcodes I can refer to?

 

Yes, I'm using an oiler and the fan is running. I'm still using only PLA and will likely do so until I can get all these bugs ironed out.