As I understand, on a SE it is that big hunk of crap located between the two 5 and 6 port actuators. Since I got rid of my cat and went RB presilencer, word was I didn't need my air pump. So now its gone. Word is, if I dont have my air pump then I dont need the ACV. I did see that the purpose of the ACV is so the engine doesn't backfire after high accel or during shifting. Mine never did that anyway. So can I get rid of it and put on the block off plate or will it start to backfire????

 

The ACV has ZERO purpose if the airpump is gone.The ACV routes the pumped air to either the ports,cats or atmosphere....so no pump,no air to route!
Just be sure to install the block off plate and cap any vacuum lines.