The engine is numbered 1234 on the right (pass) and 5678 on the left (driver)side. I did not do the valve cover gaskets. The only part that I "threw" at the car was the MAF and I only did that because I took the TB out cleaned it. I did the intake Gaskets because I found a small leak at the donut gasket in the runner to #7. I have switched coils left to right and there was no difference. I used the F8DC4 plugs. I was able to get into the ECM with a Solus Ultra with the latest software. The o2 voltage range before the cats was 86-826 on the left and 126-626 on the right. The o2 (Lambda) control before three way cat converter was -2.1--1.3 on the left and 0.2-0.3 on the right. I realize this might be all greek because its coming off of a Snap On tool and not from a Mercedes scan tool. I'm not well versed on (Lambda) control. I found the differences in the lambda voltage readings interesting. Right now I'm leaning towards doing a pressure test in each side of the exhaust system as I am suspecting a restricted cat.

I really appreciate all your help guys.