Rattle from Vibration (Page 1/1) Mct2green AUG 19, 01:19 PM I have a minor vibration "rattle" or sound around 2700 rpm coming from behind the center console. It only happens when the ac is on. I just did a r134 conversion and everything is working great. I have checked all of the heat shields. I can reproduce the sound while sitting still and revving the motor to 2700 rpm. Its not a belt sound. Anyone ever had a sound like this? Its not very loud but enough to be annoying. I thought it was coming from the dash area, but when I move the passenger seat forward, I can hear it more. I am stumped 2.5 AUG 19, 01:23 PM Think its in the engine bay / other side of the firewall, or interior parts in the cabin? One thing I have had happen.. and someone else has as well, is the guts in the catalytic converter came loose. A quick check for that is when the car is off and cool, just get under there and hit the cat, see if it rattles.