Rough idle

MONTECARLOLT06

MEMBER
2006 CHEVROLET MONTE CARLO
6 CYL
2WD
AUTOMATIC
19,789 MILES

Hello my name is Sam I have a 2006 Chevy Monte Carlo LT 3.9L. I have a few questions. First: When my car is idleing it will shake not like violently but enough to notice most of the time. The RPM's don't really move just sumtimes and it just moves a hair do I have to be worried about this and what can I do to fix it? Second: When sitting at a red light car in drive and not moving I feel vibrations and notice no RPM movement what is this and what is the problem? Is all this causeing damage to the engine? The car is in great shape and new. Third: when stopped at a red light and car is not moving I take my foot off the brake and let the car roll alittle it shakes but no RPM movement at all I had asked someone and they said its because the engine is not getting gas but it seems to happen all the time just like that is it normal for my car or is it fixable? Thanks so much -Sam-

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

There are a couple things that can cause this but the fact that it seems to go away when you are moving then this could be an engine mount issue.

However, let's start by checking the fuel pressure and for a vacuum leak because these are the most common issues.

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

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

The mount is there to insulate the chassis from any engine vibrations so when it fails you can actually feel them, and it is worse when not moving.

https://www.2carpros.com/articles/how-a-motor-mount-works

If all these check out, then we are going to have to dig into this guide and see what we turn up:

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

Please let me know and we can take the next steps after this.

Thanks