Q: Q: engine revs up and down when in park

asked by on

engine revs up and down when in park and when driving

My car has 130170 miles.
My car has an automatic transmission.

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.

A mechanic will be able to diagnose the rough idle for you and quote the needed repairs. For this vehicle, the engines are very sensitive to vacuum leaks in the intake air tube, between the mass air flow sensor and the throttle body. If the tube is cracked it will need to be replaced before anything else to see if the idle settles down.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Q: engine revs up and down when in park

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Above you give information for correction on the fuel cap, but where is the "next" button?

Hi there. The message is on for the fuel system is not able to build up pressure. Check the fuel cap seal and see if the seal is cracked or broken. A broken seal on the fuel cap will cause...

Q: Car stalls out of nowhere

Hello - what a frustrating problem to solve! You may have provided a key clue to the solution, given that it requires another vehicle to jump start it to get it going again. This MAY mean that the increased starting...

Q: Sometimes my car accelerates very slowly but the RPM rises

Hello. I would recommend first checking the connections to the MAF sensor and cleaning it as sometimes they will get dirty and cause this kind of problem. If this does not work you may need to have it replaced. If...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.