The thermostat in your vehicle isnt a typical type, but rather controlled by the DME, or engines computer.
That code is for a fault in the system, and more often than not requires a new thermostat to be installed
Nothing was posted about any misfire issues?
There is only 1 thermostat, it regulates the engines temperature by allowing coolant to pass through the radiator. More often than not, they stick in the open position, which means your vehicle will never fully get to operating temperature.
This code COULD cause some misfires if the vehicle is never entering its closed loop fuel status, but hard to say at this point. This is a condition that needs fixed first then w can further diagnose the problem
I see now it was posted twice, first post with some more information about the misfires.
Thanks for the accept, let me know once you get a new thermostat and if the misfires still persist, do everything I can to help you out with those!