idles fine, will not accelerate and tries to backfire. o2 sensor or catcon? on 2002 Saturn L100

the car suddenly started losing power and the engine shook really bad. it starts fine but will not accelerate. it seems to idle smoothly but when the accelerator is pressed the engine surges . And it seems to be backfiring when the gas is pressed.

Asked by for the 2002 Saturn L100
i would check for a stoped up conveter, you can remove the upstream o2 sensor or unbolt the exhaust pipe going into the converter, then start the car and see if it will rev up.
I will try that. Thank you! If its the convertor, I already know how to fix that. a long rod and a