check engine light on 1994 Volkswagen Jetta

My check engine light comes on & the power seems to go down. After a while the light goes off & the power is back to normal. Any suggestions?

Asked by for the 1994 Volkswagen Jetta
Do you know the fault code associated with the check engine display?
Look under the hood for loose electrical conections and check all the hose attachments , especially between the intake manifold and air cleaner. Physically test them by wiggling to be sure they are tight.
If the engine simply loses power but does not miss or run rough you may have a mass air flow sensor issue. While the symptoms are evident try driving with the mass air flow sensor disconnected. If things improve your mass air flow sensor is suspect.
Get the vehicle scanned , Kragen or Auto Zone stores offer this for free , and see what the fault label is.