2005 Cadillac STS engine vibration at idle

Does it change with engine speed, or go away? One way to narrow it somewhat is to remove the serpentine belt to stop accessory rotation. If it goes away, accessories may be at fault. At that point, the crankshaft, and torque converter would be the largest rotating mass. Is there a check engine light on/flashing?, this would indicate potential misfire.

I done all that before hand I even replaced the crankshaft vibration damper. The engine only vibrates at idle, but run like a raped ape down the freeway.
As for engine codes it has done and it does not store codes because it has a can-bus system. I been working on cars for 25 years I never seen one do this.

Not storing codes because it has CAN makes no sense to me. What are you trying to read codes with? HAs there been any repairs to the engine that may have some relation to this vibration?

It makes no sese to me to; GM can't tell even tell me whats wrong with it, I just had the car go though the state inspection here in Texas and it pass with flying colors. I ask the tech if there are any stored codes it has none.

If the vibration has been compared to a similar vehicle, and has been determined unacceptable, the next step would be to disconnect the torque converter and remove the belts. If the vibration is still present, that would narrow it down to an engine imbalance. If it goes away, then I would try re-indexing the torque converter first. It has three bolts that hold it to the flexplate. Try another mounting position and see if the vibration changes.

I will give it try this weekend, I sure let you know if it works or not.

Hi,

Sad, there was no response. I am having the same concern for a few weeks ....
It's intermittent. It seems to me that very hot, there are no vibrations ... But hey, I wanted to fix this little problem.
Same Vehicle, Cadillac STS 2006 V6 automatic ' Automatic two-wheel drive (rear-wheel drive).

Sorry they did not respond with what fixed it. Unfortunately that happens but we really want people to come back and close the circle so that it will help others (like you) in the future.

However, if we figure out your issue then that will help others in the future.

So let's start with the basics and make sure we don't make any assumptions.

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

If the engine only vibrates at idle then the most likely cause would be an engine mount or a possible small vacuum leak.

So let's inspect both of these as well.

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

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

Once we work through these items we will have a better idea on what to do next so let me know what you find.

Thanks

Hello,

Thank you for the return, perfect, I will take care of checking these points.
Indeed, it is only at idle, but the engine has not failed...
The power is perfect

I'll come back to explain, but I need time...
Thank you

No problem. That is good info. The fact that there are no performance issues and the vibration goes away points to a mount issue. However, if this is a small vacuum leak then when you raise the RPM and the PCM introduces more fuel, it evens out the air/fuel enough to smooth it out.

Let us know what you find, we will be here when you do.