2000 Cadillac Seville There is no power when I push the gas

Check and see if the snorkel is off at the throttle body, or if that plastic resonator has come loose at the air inlet tube. It sounds like an air leak after the mass air flow sensor, the map sensor code will set falsely due to expected vs. Actual engine vacuum based on airflow readings and throttle angle. The resonator is the piece that you have to lift up off of the pin to change the air filter.