Ok my GTP has about 67K on it. Has clean oil, less than 100 miles ago the injectors were cleaned with Sea Foam, and had spark plugs changes (AC Delco).
When the vehicle is in park or neutral (i like to put into neutral sometimes so I dont have to hold the brake. Im used to stick) it will rock a little bit. The RPM Gauge doesnt bounce our anything out of the ordinary. There are no odd sounds coming eather. Just a light rumble in the seat and floor. It will happen about every 7 seconds. It is definitely noticeable by me and a passenger.
I am a little concerned on why this is doing this. Any suggestions?
Thank you!
