Engine low idle and vibration?

KAMRONP

MEMBER
2009 TOYOTA COROLLA
1.8L
4 CYL
2WD
AUTOMATIC
120,000 MILES

Hi, I hope this is the right area. I have the car listed above, I purchased it with almost 116,000 miles on it. I used to have a high idle I went to fix my front motor mount and when started to drive home once it warmed up it started vibrating at the stoplight. When it warms up it vibrates when in idles and reverse. I changed spark plugs and fuel injector and carburetor cleaner. I don't know what else to do the check. Engine light is not on and when they plug in computer checker nothing comes up. Does anyone have ideas? I have also recently replaced cabin air filter and air filter. I did an oil change and transmission flush. Also replaced a engine coil (which check engine light came on for) and serpentine belt and also my front struts.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Welcome to 2carpros.

Since you just did work on and around the engine, my first suspect is there is an engine vacuum leak. Here are directions for testing for a leak. Do this and let me know what you find. Also, recheck to make sure no vacuum lines were disconnected or damaged. Make sure the air induction tube between the air filter and throttle body is properly installed and tight. Any unmetered air entering the engine can cause a rough idle. Here are links that you may find helpful.

https://www.2carpros.com/articles/engine-vibration-at-idle

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, let me know the engine idle speed when you notice the issue. It should be between
600 and 700 RPM's and also if the idle increases slightly when the AC is turned on.

Let me know the results.

Take care,
Joe