I think its a combination of pinching the filament too tightly against the hob/ or too loose and stripping it or the hotend is jamming which is unlikely unless there is something in the filament that caused it to jam. I can print ABS at 220C without any issues with no fan, but long prints (3+ hrs) will eventually cause issues for me as the heat travels up.
But Bobby, If you want the start and end .gcodes I use let me know. It ill pre-purge the nozzle for you, and once the print finishes move away.
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Kreativ-e
Tinkerine Studio