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Q: Throttle Positions VS Voltage Fluctuation

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More obvious at night! Engine runs smoothly until the throttle becomes more demanding. Tach indicates RPM fluctuations,1 to 3 hundred, as more acceleration is required on upgrades; cruise or manual. Headlights and dash lights indicate a voltage fluctuation upon slight increase of accelerator demand on upgrade.

My car has 95000 miles.
My car has an automatic transmission.

This may be related to a couple of different possibilities such as a faulty throttle position sensor or potentially a faulty instrument voltage regulator. The throttle position sensor (TPS) is a sensor used to monitor the throttle position of the throttle plate inside the throttle body in relation to your foot position on the gas pedal. Based upon the inputs from the sensor reading your foot’s position on the pedal, the ECU then makes the direction to supply more or less fuel to the motor. When this sensor is not working properly, this can cause intermittent responses when pressing the gas pedal.

The instrument voltage regulator regulates the voltage supplied to the various gauges in your vehicle’s dash. When this is not working properly, this may cause the gauges in your dash to dim or flicker erratically or in some cases provide false readings. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your instrument voltage regulator.

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