Why does my car engine rev up and down when in park?
The idle is controlled by the idle air control valve and if it cannot keep the engine idling it will keep trying to rev the engine up to compensate. A vacuum leak, sensor that has failed, or an EGR system malfunction could potentially be the cause of the erratic engine you’re experiencing.
Why is my car revving on its own in park?
It sounds like you may have a dirty or failing idle air control valve. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage.
What causes surging at idle?
If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.
Can a faulty oxygen sensor cause engine surging?
Oxygen sensors are among the most interesting and important sensors on your engine. Surging is among the many problems a failing O2 sensor can cause, but it isn’t the only one.
What causes a motor to slow down then speed up?
A poor O-ring seal in the fuel fitting can allow air to suck into the system, especially when the hose is flexed in turns. This WILL reduce fuel flow, and if allowed to continue can lean the upper carb (s) and burn a piston.
When does a car idle high and accelerate on its own?
It happens when no gears are engaged, acceleration pedal is not pressed, and brakes are activated. Idling is needed in many situations, such as when you wait for the traffic signal to turn green or at any point when you don’t feel the need to turn off the engine. Sometimes idling seems to increase the RPM high until the engine is fully warmed up.
Why is my Honda Element engine surging in Park?
Check all of the vacuum lines, and the small rubber cap on the under side of the intake manifold (tough to see). You could also try replacing the idle air control sensor~$75. Check the coolant level, it might be low causing the intake air bypass thermal valve to cool off and raise the idle speed.
Why does my Honda Civic have a high idle speed?
Check the coolant level, it might be low causing the intake air bypass thermal valve to cool off and raise the idle speed. This happened on my civic. If the battery is low or has an internal draw it could cause this. Also if the altenator is having problems, it could lead to a high idle.