The TPS monitors the mixtures of air and fuel being delivered to the engine, providing a signal to the fuel injection system as to the power needs of the engine. Symptoms of a bad TPS include loss of power, poor fuel economy, lack of power during acceleration, won't shift up, sudden acceleration while driving, poor idle or stalling. The check engine light is illuminated when the TPS fails. Regitar-USA products are manufactured to meet or exceed OEM specifications and are tested for quality and performance.