Car sounds completely different at start up... almost hollow. RPM at idle are 700... Car is not putting out as much exhaust and is much quieter at idle and under load... very weak on acceleration...
On another board, you added that there was a knocking sound from the bellhousing area? You may have a clogged cat and the noise is the loose guts rattling around inside of it.
Yes, pull codes from the computer and report back with the code numbers and desciptions if you can. These symptoms could be caused by any number of issues and the computer will help you narrow it down based on what it sees.