My 1989 cutlass ciera is losing power while driving

Hello, When the only symptom is loss of power, it is impossible to advise what it may need without inspecting the vehicle. This could be anything from a fuel issue, to a clogged catalytic converter. Evan being a 1990 model, there are methods for reading trouble codes if the check engine light is on, and people make videos about doing it without scan tools all the time. Whether or not the check engine light is on, you are likely best off bringing it to a professional for diagnosis.