Is it safe to assume I have a vacuum leak in the secondary air injection pluming if I disconnect the air pump electrically at the pump and my engine idles slower and real poor? I have the 02 sensor disconnected and have the computer seeing a constant 4.8 volts. This seems to stop the 3K hesitation and it idles OK not great but much much better than when the pump is off.

 

I don't think you can make that assumption. The air pump feeds air into the engine as well as the cat. via the ACV. When I removed my air pump it messed up the idle (slowed down sometimes, varied others). The Apex'i PFC fixed that problem!

 

and the AVC is ??

 

This is a switching valve for up stream and down stream air distribution. The intake it self is not open to the pluming with in the system. Is that correct. The intake is not open to the system at all not even if a diaphragm is damaged? is that correct? How else would it effect idle besides the load it pulls. I can see how the air pump could skew the fuel mixture if its pumping air to the 02 at idle. The system would see a real lean signal at the 02 sensor and go rich. but off its not the case. Thoughts ?