Here is the issue I'm having. It is much more then your basic everyday secondary air injection fault.
I have had my car for 2 years and have been endlessly chasing this issue on/off for that time. Nobody, not any of the local shops, or the dealer, can figure out what the cause is. It will cause check engine light to come on every other month or so, then it will go off, then back on again.... and the problem will go away for 2-3 weeks, then it will return again and throw the same code. I have replaced the MAF, spark plugs, checked all the air injection lines, checked the sec air pump, replaced the 02 sensors (dealer came back and said replace these, so I did and it did NOTHING). I have replaced the check valves in the sec air injection lines also. Nothing has solved it!! It is driving me cazy!!!!
Here is what happens
My car sits in a garage at night. When I leave for work at around 8am in the morning, I hear the secondary air pump come on for about 60 seconds... I pull out of my street and hit the first red traffic light about .75 to 1 mile down the street. As soon as the car goes to idle, I hear a click behind the dashboard, all the lights in the car dim and the pump turn on for 5 seconds....THE VERY SECOND THE PUMP TURNS OFF... the car stumbles and acts like it wants to stall.... it recovers, and then after another 10-15 seconds I hear the pump come back on again....THE VERY SECOND THE PUMP TURNS OFF... the car stumbles and acts like it wants to stall again. The process is repeated over and over until the car is at and has been at operating temp for some time. The pump was still short cycling after a 7-10 mile drive during one of my tests last week.
When it is stumbling....the idle goes from 600-700 RPM down to 300 RPM, ONLY FOR 5-10 SECONDS....the car lurches forward....it feels like it is going to stall....all the lights dum....the whole car shakes....the tach needle floats up/down wildly......then it rebounds back to 600-700. CEL P0410 will come on after one day.
I can unplug the pump or disconnect the tube over to the valve and it will run fine. CEL will come on.
Friend read o2 sensors from cold start and determined that half the sensors were seeing the injected air and half were not. He suggested that cylinder head ports were blocked with carbon.