I just removed the air pump from my 91 vert. I've been doing some research but cant find any solid answers on how to make sure my 5th and 6th port actuators are working. The car definitely seems to lack power at higher rpms. Please help!

 

The air pump runs the 5/6 ports on the S5 cars.

 

FREE FSM: 1989 N/A Fuel and Emissions Control Systems

^ Halfway down the page. (F1-42 to be exact.)