Try one or 2 of my NodeMCU examples that are known good for the current Arduino core,
Only to be used with ArduinoIDE 1.6.8 ... it may work on later versions, it may give errors.
What you are seeing on the serial terminal is a stack-dump caused by something in code ... or the WDT firing. In any event, try my NodeMCU without WiFi to see if you can get the system to be stable.
IMO the #1 cause of ESP8266 issues is a poor power supply / that is, either noisy or poorly regulated. When the WiFi kicks in, the current can spike to 750 - 800mA. The quick pulses of current can create dips in voltages inside and outside the chip due to resistance. It is absolutely mandatory to have a good power supply.
Ray
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