Thanks MB for the quick responses and info. You have been very helpful. The last activation I did was last Oct ($90) and the O2 information came from it. I was also told that there could be possibly carbon build up in the ports and that this has been cleaned by diyers but I never found out the proceedure. Last week I had codes ran because of a slight miss while driving in traffic no noticed as much when on the highway. The O2 showed not reading. I have never replaced the right front but had replaced the left front as I meantioned earlier. I replaced the FR O2 and reset the ECU according to procedure found on forum and the problem went away. I still have the CEL with PO410 code in the mornings only after setting overnite. I have had the full code and activation run twice in the last 2 years ($90 & $75 respectfully)with no reasonable explaination. Please do not get me wrong I do not mind paying for results I am just unable to pay out with shrugged shoulders be the result. I appreciate your help as always and I continue learning more and more which has helped more than you know. Best Regards MBD