bhauto

I just got a 2009 Cl63, need some advice on a misfire and low power situation. I have two cylinders misfiring, as well as low power when you really give it some gas. I changed the coils and plugs as well as did a compression test, all good.

Codes on the computer are
P0040-Oxygen sensor signals swapped Bank 1 sensor 1 / Bank 2 sensor 1
P0300- Random misfire
P0301- Cylinder 1 misfire
P0304- Cylinder 4 misfire
P0302- Cylinder 2 misfire

Not sure where to go from here, thinking maybe a short somewhere in the harness?

Any advice would be greatly appreciated

3630stephen

i'd first look at your o2 sensors there is obviously a fault there they read your emissions and tell the brain weather to add or take away fuel running lean can cause miss fires also check all your vaccum lines for any air leaks that will throw your mixture out as well but that will make it run rich because to much air is entering the system the brain will add more fuel how does your exhaust smell have a sniff the other things to look at are faulty injectors or a weak fuel pump but the diagnostics are pointing to the o2 sensors good luck

bhauto

Forgot to mention, I did replace the o2 sensors, and swapped them just for good measure. Codes still remained there. Why I was thinking a short somewhere

3630stephen

that was going to be my next suggestion the error code does suggest that your primary pre cat o2 sensors have been plugged in the wrong way round but if you have already tried that i'm stumped what i have learnt with mercs is nothing is ever that straight forward

cl63amgtapatio