96 altima bad idle almost stalls in park does when releasing clutch Help?

Vehicle starts but barely stays running. Theories are bad cat or o2 sensors or possibly bad egr valve. Has spark and compresson unsure of fuel pressure. when I push gas pedal to floor it sputters up to 1500rpm and almost stalls out barely stays running. When releasing clutch it will stall. Any ideas? Thanks for any help given or ideas