Vehicle losing power and eventually shuts down not wanting to restart

What is your question?

I purchased this car but the original engine had already been changed to VVT engine and rewired, Since then, the temperature gauge has climbed when going uphill but further observations showed the vehicle is actually not overheating and there is no restriction in the airflow system. OBDII code P0443 is present and we have replaced the temperature gauge sensor at least 3 times and the airflow sensor as well.I'm lost now...