I'm just thinking out loud.
Doesn't the air pump, pump more air into the cat so that it will burn exhaust gasses more completely? I think that is in response to the O2 sensor.?
I suspect it has something to do with the O2 sensors and the air pump.
There are two O2 sensors on that bank. One in the exhaust manifold, and the other just after the CAT.
Did you pull codes? |