Question

2005 Mercury Monterey 4.2L with engine code P0180. What will the fuel temp sensor circuit do to a car if it goes bad?

Answer 1

P0180 Fuel temperature sensor "A" circuit

This depends on which one you have Ford has 2 different types that are used with this  make and model, If you have the fuel temperature sensor that is seperate from the fuel rail pressure sensor, which is the FRT (fuel rail temperature) sensor the ECM uses this to adjust fuel injector pulse width and meter each fuel injector to each cylinder, if this is faulty the fuel economy is depreciated. If you have what is called a FRPT ( fuel rail pressure temperature ) sensor this is used to control the speed of the fuel pump,and give fuel according to engine load, if this is faulty you will stall out unexpectedly.

Answer 2

P0180 Mercury Code - Engine Fuel Temperature Sensor 'A' Circuit
Read more: https://www.autocodes.com/p0180_mercury.html