One thing I'd like to add is that the so-called "redundant port blocking" is not good. Using this diagram and a bottle of compressed air, I verified that this port is the air output for the economy device. The economy device is supposed to open up an air circuit to help emulsify the mixture (lean it out) during idle and part throttle conditions. If you block the port, the economy device never gets activated. Therefor you get terrible fuel mileage but increased power. I took a 400 mile trip last weekend and I could literally watch the fuel gauge drop every couple of minutes. I got 9 MPG at 60 MPH on the highway. The misture was so rich that I could smell gas in my oil
After the trip, I unblocked the port and now I'm getting the normal 15 MPG. But the top end power has decreased a little.
