Possible causes of a car idling high while in park include the car having a bad accelerator, an overheating engine, the fuel pressure regulator operating at low pressure and the alternator acting up. One symptom of the car's idling problem is the driver having to apply brakes intensely when parked.
Each of these possible causes has an easy solution. The accelerator and alternator can be replaced if they are diagnosed as malfunctioning. The overheating engine can be repaired, though a certified mechanic will need to check the cooling system. The fuel pressure regulator can be examined with a fuel pressure gauge and replaced by a mechanic as needed.Learn More
A car will boost to a higher revolution in park if the idle is set improperly or there is a leak. This will also happen if the idle becomes stuck or the oxygen meter indicates it needs to adjust the oxygen-fuel mix.Full Answer >
Idle speeds vary from car to car, but for a passenger car, typical idle speeds are between 500 and 900 rpm. This idle speed also depends on the accessories that are currently running as a car's idle control system will automatically raise the idle in order to provide power for auxiliaries such as air conditioning and power steering.Full Answer >
The number one cause for high idle is an imbalance in air pressure. An engine that is idling too high may be caused by a faulty idle air control motor valve that has completely failed or that has simply become weak and is not functioning correctly.Full Answer >
A car or car's engine may vibrate while idling for various reasons, including that the motor or transmission mounts have a problem. When a car is stopped at a red light or turned on in park, a noticeable vibration may occur that signals damaged or broken transmission mounts.Full Answer >