Why is my car jumping while idle? Need help!

Technical Discussions
1

I’ve been noticing that my car starts jumping a bit when it’s idling, and it’s really starting to concern me. Here’s what I’ve observed about the situation:

  • Engine Vibration: When I’m at a stoplight or just parked with the engine running, it feels like the car is vibrating or bouncing slightly.
  • Noise: There’s a faint noise that seems to correlate with the jumping, almost like a light sputter.
  • Check Engine Light: Recently, I noticed that the check engine light has also come on, which I suspect might be related to this issue.

I’ve done some research and it looks like there are several potential causes, but I’d love to hear from those of you who may have experienced this:

  1. Engine Misfire: Could a misfire cause this kind of jumping behavior?
  2. Idle Air Control Valve: Some mentions of the idle air control valve not functioning properly caught my attention. Has anyone dealt with that?
  3. Vacuum Leaks: I’ve read that vacuum leaks can lead to erratic idling. Is there a way to check for that?

I’m hoping to get some advice on what steps I can take next. Should I start with a code reader to check what’s triggering the check engine light first? Or is this something a mechanic should look at immediately? Any help or suggestions would be greatly appreciated! Thanks in advance for your insights and experience!

2

It sounds like your car might have an issue with the idle air control valve. This can cause erratic idling and make it feel like the car is jumping.

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3

That makes a lot of sense! I also read that fuel injectors can cause similar problems. Have you checked those?

4

Definitely check the spark plugs too. Bad plugs can cause uneven firing and lead to shaking at idle. It’s an easy fix if that’s the problem!

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5

I know a friend who had that issue. Replacing spark plugs made a huge difference.

6

I’ve heard that vacuum leaks can also cause rough idling. If there’s air escaping, it can mess with the engine’s performance.

7

That’s a good point! I had that problem once, and it was pretty simple to spot. Check hoses for damage.

8

It might also be an issue with the EGR valve getting stuck. A stuck EGR can cause poor engine performance, especially when idling.

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9

Has anyone ever had a problem like this due to a bad fuel pump? I wonder if that could be at play here too.

10

I had a car that shook at idle, and it turned out to be a weak ignition coil. So don’t rule that out, either!

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11

Good tip! Ignition issues can be sneaky but definitely worth checking.

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12

How old is your car? Sometimes, older models just have quirks like that. A good tune-up may resolve many issues.

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13

Honestly, it sounds like your car is just testing your patience! Mine does that sometimes, but it’s still reliable…mostly.

14

Haha, I completely relate! Sometimes I think cars have a mind of their own!

15

Sounds frustrating! Many factors can cause a car to jump while idle. First, check for vacuum leaks in the intake system, as they can affect engine performance.

16

That’s a good point! I experienced something similar, and a loose vacuum hose was the culprit. Ensure all hoses are securely connected.

17

You might also want to inspect your engine mounts. If they are worn out, they can cause the engine to vibrate more than usual during idle.

18

Great advice! I had a similar issue, and replacing my worn engine mounts made a huge difference.

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19

Don’t forget to clean your idle air control valve. A dirty valve can lead to rough idling and jumping. It’s a relatively easy fix!

20

I completely agree! A simple cleaning can resolve many idle issues. Just make sure to use the right cleaner for it.