Why is my car idling high in park?

Technical Discussions
1

I’ve been experiencing some high idling in my car while it’s in park, and I’m trying to figure out what’s going on.

Potential Causes

  • Vacuum Leaks: One common issue that could lead to high idle RPMs is a vacuum leak. This means that air is entering the engine without passing through the throttle body, causing it to rev higher than normal. Check hoses and connections for cracks or disconnections.
  • Throttle Position Sensor (TPS): If the TPS is malfunctioning, it may send incorrect signals to the engine control unit, causing higher idling.
  • Idle Air Control Valve (IAC): This component helps regulate the engine’s idle speed. If it’s dirty or failing, it might not control the idle properly.

Normal Behavior

It’s important to know what a normal idle RPM is for your specific vehicle make and model. Generally, most vehicles should idle between 600-900 RPM when in park. However, higher idles can also be normal based on engine temperature and load conditions.

Troubleshooting Steps

  1. Check for Error Codes: Use an OBD-II scanner to check for any error codes that might give clues about the issue.
  2. Inspect Engine Components: Look through the engine bay for any visible wear or disconnections in vacuum lines.
  3. Clean the IAC Valve: Sometimes, simply cleaning the IAC can solve the high idle issue.
  4. Consult a Mechanic: If you’re not comfortable troubleshooting, it might be safer to get a professional diagnosis.

Has anyone else experienced this? What did you find was the cause? Looking forward to hearing your thoughts!

2

I’ve noticed high idle can often be linked to a vacuum leak. Have you checked your hoses for cracks or disconnections?

6 Likes
3

That’s true! I’m also concerned it could be a faulty TPS (Throttle Position Sensor). Those can definitely cause erratic idling.

4

Good points already mentioned! Don’t forget to check the IAC (Idle Air Control) valve too; it can lead to high idle if it’s stuck or malfunctioning.

5 Likes
5

Right, Sean! And what about resetting the engine control unit? Sometimes a reflash can fix weird problems like this.

6

Make sure to check for any error codes if you have an OBD-II scanner. It could lead you directly to the source of the problem.

7

Great advice! I usually overlook that step. What if the high idle is just a quirk of the engine? Sometimes cars have personality! :joy:

8

Haha, good one, Mary! But seriously, a high idle could also indicate vacuum leaks or even an issue with the throttle body itself. A thorough check is necessary.

4 Likes
9

True! I have heard of folks soaking the throttle body in cleaner to prevent sticking. Could be worth a try!

10

Does anyone else think this high idle issue could just be related to engine temperature? Sometimes engines rev higher when they are cold.

1 Like
11

Excellent point! A malfunctioning coolant temperature sensor might cause this too.

12

If all else fails, I’d recommend a good mechanic check it out. Sometimes these things are tricky and better suited for professionals.

13

That sounds reasonable. I hate to admit it, but I once ignored a high idle and it led to bigger problems. Lesson learned!

14

Thanks, everyone! This has been really enlightening. I’ll keep you all updated on what I find.

3 Likes
15

High idling can definitely affect your fuel efficiency. The engine runs richer in fuel, which can lead to increased consumption. Have you noticed any changes to your gas mileage?

16

Great point! I’m actually looking at a decrease in fuel efficiency lately. Could it be tied to this idling issue?

5 Likes
17

When your car idles high, it can also lead to increased wear on engine components over time. Make sure to keep an eye on that to avoid bigger issues down the line.

18

Exactly! My mechanic mentioned that excessive idling could cause additional strain on the engine. How can we diagnose this properly?

19

High idling in park can also lead to potential safety hazards, especially if your engine is struggling. Have you experienced any rough idling or engine stalling?

20

Yes! My car has been stalling occasionally. Could high idling be causing this?

6 Likes