The heat shield on top of the converter may have broken loose. it can be repaired. If the rattling is inside the converter it must be replaced.
Replace it.Replace it.
More than likely the heat shield is cracked or loose. Repair or tighten it.
No.
Check that catalytic converter is not plugged
Gets clogged
Engine mounts
Yes if it is totally clogged.
Take your foot off the brake You may have either a misfire or a plugged catalytic converter. Is the check engine light on or flashing? Does it sputter or is there a loud throaty noise?
Yes, if it is clogged very badly.
There are a few things that might cause an air conditioner to make a rattling noise. It could be that the there is dirt and debris in the cabinet. If this is the case, cleaning the cabinet should stop the rattling. The reason could also be loose panels on the cabinets. The fan could also be bent and no longer straight.
Check for plugged: fuel, air filter, catalytic converter
A bad catalytic converter and stopped up muffler will slow down the car. The catalytic converter is under warranty up to 84,000 miles, if defective. If you ran over a speed bump and damaged it, you have to replace it. You can buy a lower catalytic converter for $120 from advance auto parts.