After header install Vibration in idle and gets worse when in gear help


New Member
Nov 4, 2018
Hello everyone i've got a bit of a weird issue that I can't seem to figure out.

I recently brought my car into a shop to get my shorty headers installed after my DIY failed attempt caused the EGR seal to break and that came with check engine lights and running lean codes and I just gave up. Anyways I brought it to a shop my neighbor owns and he was able to do a custom install because the headers didn't quite fit right but he and his crew did a good job from the looks of it. Everything runs great and sounds amazing but now I have a really annoying issue in idle.

When the car is in park and idling it is perfect at first but a vibration slowly comes up and it has a mild noticeable vibration that can be felt everywhere. When it is in gear like Drive or Reverse that is when the vibration feels like something might be getting damaged and is pretty rough. It ONLY happens like that when it is not moving. The second I start to drive it is perfectly fine no problem.

I know its not motor mounts because this only started happening right after the header install. I don't know how it could be the exhaust rubbing on something because it gets way worse when in drive or reverse at a stop and the RPMs do not change.

Things about the car that might help:
94k Miles
2010 V6
BBK Cold Air intake
PaceSetter Shorty Headers
Flowmaster American Thunder Exhaust

His explanations for the vibration do not make sense because he said that it was probably rubbing because the headers were not a perfect fit that is why I am here.

Is there anything I could do to better diagnose this?
I appreciate any help
This is the car
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