Answer A is wrong. A leaking fuel injector will cause a rich condition.

Answer B is wrong. A faulty pressure regulator will cause a rich fuel condition.

Answer C is wrong. A faulty ECT will cause a rich fuel condition.

Answer D is correct. A stuck closed thermostat will cause a vehicle to overheat. A thermostat in the stuck open position delays or prevents the engine from reaching its optimum operating temperature causing the PCM to alter the fuel trim accordingly.

Answer A is wrong. Both technicians are correct.

Answer B is wrong. Both technicians are correct.

Answer C is correct. An oxygen sensors heater circuit is designed to bring the sensor to operating temperature and closed loop quickly. It sends a voltage signal to the engine control module in closed loop.

Answer D is wrong. Both technicians are correct.

Answer A is wrong. The wastegate is controlled by a valve and releases excess pressure back to the exhaust stream. This device is used to control intake manifold pressure.

Answer B is wrong. They are both right. When the gate opens exhaust by-passes the turbine wheel reducing intake manifold pressure.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

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Answer A is wrong. A rich fuel mixture will likely increase HC or hydrocarbon emissions.

Answer B is wrong. A clogged catalytic converter will result in an extreme loss of power.

Answer C is wrong. A cylinder misfire will result in excess HC's resulting from unburned fuel.

Answer D is correct. A stuck closed EGR valve will result in high cylinder temperatures and high NOx in the emissions.

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Answer A is wrong. It is correct that a voltage drop test would verify a poor or corroded ground circuit.

Answer B is wrong. It is also true that a voltage drop test is a great way to find resistance in a circuit.

Answer C is correct. Both technicians are correct.

Answer D is wrong. Both technicians are correct.

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