No.
Check that catalytic converter is not plugged
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.
Leaded petrol cannot be used in a car with a catalytic converter as it contains lead which would form a coating over the working surfaces and stop it contacting the exhaust and treating it. This is also known as Catalyst poisoning.
Replace it.Replace it.
Gets clogged
Engine mounts
Yes if it is totally clogged.
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.
Yes, if it is clogged very badly.
Check for plugged: fuel, air filter, catalytic converter
That is possible.
You have 2 options. Either you put your catalytic converter back on or you unplug the check engine light. Thanks for killing the environment.