Installed a wideband in my car, and wow is my car running rich!

I think your AFRs are just tune / load related...Interestingly the factory tune runs very rich after 5000 rpm (low 10's).
Unfortunately, nobody (that I know of) has really dissected the ECU code and made the information readily available so we could be sure there are not other factors driving the fuel and timing logic. OpenEcu for the MB platform sure would be nice....
I used to tune GM vehicles using HP Tuner and it was absolutely amazing... especially at $400 ( back then, don't know now ).




