Sorry to bother all of you but I’m having the Check Engine Light - P0410 code again. All was good for a couple months but the CEL and P0410 code is back. I am looking for ANY suggestions as to what to check or where to check.

Over the past year I have replaced the following in the Secondary Air Induction System … O2 sensors, right and left air valves, air pump, blue vacuum check valve, air induction system change-over valve, and the RCM has been rebuilt. I have not made any other changes to the vehicle.

On the first start after clearing the P0410 code I do not have Check Engine Light, after the first start I can get the Check Engine Light and the P0410 code right away or it may take several starts before it returns (as many as ten starts) … there does not seem to be a pattern to the Check Engine Light and the P0410 code returning.

Any ideas or suggestions as to what to check, where to check is greatly appreciated … I am lost at this point.