I have a 2006 EX I just bought used a few days ago. It is my first civic. When I start it up, it is very smooth at idle. After I drive it for awhile I can be at a light stopped and the car will vibrate. I can sometimes hear a rattle from the plastic when I put pressure down on the console between the seats with my right elbow. At some lights (anytime coming to a stop) it doesn't do this. I just replaced the spark plugs to see if that would help. I also replaced the oil and air filter. My mechanic recommended I run sea foam through the car to see if that would help. Everything about this car seems perfect, except for this vibrating idle that happens 50% of the time. I can feel the vibrations coming up through the seat. At idle when it vibrates the car is pulling 700 rpm. Is that rpm normal? Any idea what is happening?


THANK YOU SO MUCH IN ADVANCE

 

Check your engine mounts. Make sure none of them are collapsed or broken because that will contribute to a lot of vibration.

 

Good advice. I did. I had it put up on a lift at my mechanics. No problems with the mounts. The vibration comes from the engine running rough but it's not running rough. It stays constant at 700rpm. It really makes no sense. It's clearly the engine vibrating at idle sometimes and not at other times. On the interstate it is incredibly smooth. The problem is only at lights. It is most noticeable when I get off the interstate and fairly quickly come to a stop. The car usually does not have this issue when it is cold and I first start it. Any ideas at all?

 

in colder climates the interior plastic components of your car will shrink causing them to rattle on each other. if the noise stops in the summer then you know whats up.

 

I also say motor mount. If it is motor mount it will gradually get worse and louder. It will eventually sound obnoxious like a hole in your exhaust muffler.... like driving a tank if u know what that is like. Maybe not the newer tanks. OK...but seriously it is most likely the passenger side lower motor mount. My daughter brought her 06 Civic to Firestone mechanic and they told her it was a timing chain and that her mounts were fine. When she told me that, I took a look at the mount and could see that the rubber was cracked badly. I am replacing all 4 of the mounts. A loose timing chain has a completely different sound..... so do not rely 100% on what a mechanic or doctor tells you. Get a second opinion. BTW. iF it turns out to be motor mounts, you can get a set of 4 for $89.50 including shipping on ebay with a 5 yr warranty. Much better than paying $1020 plus tax at pep-boys to replace all 4.

So anyway, I see your post is a few months old. Did you find out what the prob was? Probably NOT motor mounts and i look like a fool. Good luck

 

Did you ever find out what that vibration was? Was it motor mount?