When transmission is shifted into Drive or Reverse and hit the brakes, the car vibrates violently while idling and drops to about 800-900 RPMs

Hi,

When this happens, does the A/C need to be on? Also, is it applying the brakes which causes it or do you feel it is because you put it in gear?

Interestingly, the RPMs you indicated don't seem low if it is in gear and stopped.

Here is what I'm thinking: You could have an engine vacuum leak which can cause this to happen, or there could be an issue with the idle air control valve (IAC). The IAC is responsible for maintaining idle speed. When the A/C is turned on, there is a load placed on the engine. As a result, the computer tells the IAC to increase the idle to compensate.

However, the idle speed you indicated doesn't seem bad.

Here is what I suggest: First, confirm there are no vacuum leaks. Here is a link that explains how to do it:

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

If nothing is found, try to service the IAC. Here is a link that explains how that is done:

https://www.2carpros.com/articles/idle-air-control-valve-service

Please understand, this vehicle isn't offered in the US, so I have very little technical information. Regardless, let me know if this helps or if you have other questions. I'll try my best to help.

Take care,
Joe

Good morning Joe,

It vibrates regardless of whether the A/C is on or off. By the way, it's not caused by the brakes. The vibration only occurs when I put the car in gear and it's not in motion (when the car is in Drive and you stop at a stop sign). However it stops vibrating when the gear lever is in Park or Neutral. I will check with your suggestions later today and give you an update. Thank you.

Have a wonderful Easter holiday.
Aikay

Hi,

I understand. Honestly, if there isn't a misfire, then chances are it is something like I mentioned. Keep in mind, a bad engine mount can also cause this.

Take a look through these links and see if they help:

https://www.2carpros.com/articles/vibration-noise

If you find one that is bad, here is a link that shows in general how one is replaced:

https://www.2carpros.com/articles/replace-motor-mounts

Let me know what you find and Happy Easter to you as well.

Joe