The filament not going through the nozzle and the knock of the extruder is a jam. I call it the knock of death-- I hate that noise. The fact that it comes and goes when you are moving from the middle of the print bed to the outer reaches is strange, mainly because the heater and thermistor are attached at both points and they should be reading the same within plus or mins 4 degrees of your target temp at all points of the print bed. Have you checked that the thermistor is firmly attached into the heat block and that no wiring is coming loose?
When you are printing and when it moves toward the perimeters of the bed, have you looked at the temperature in repetier host and verified that it is getting colder, and falling far outside of the target temp?
Also what hotend are you using?
When you are printing and when it moves toward the perimeters of the bed, have you looked at the temperature in repetier host and verified that it is getting colder, and falling far outside of the target temp?
Also what hotend are you using?