Steve Otter

Hi guys. I'm a long time lurker and thought I would finally post something.
I have a 2005 S55 that is misfiring all on one side, runs extremely rough(actually popped an engine mount) and absolutely no throttle response.

I've bought new plugs from the dealer for that side and nothing.
I've swapped coil packs from side to side and nothing.
I starter thinking my cat could be clogged, so I started to inspect the exhaust and noticed a cracked right after the first o2 sensor and before the cat. could the crack cause the extreme conditions?

shardul

iTrader: (1)

If you dont have throttle response, most likely the pedal assembly has gone bad.

ZephTheChef

I'm pretty sure a misfire on half his cylinders would cause pretty crappy throttle response too

But to the original question, usually if the exhaust was actually leaking at the spot in question, there would be a larger area of soot around the "crack". If it is after the primary O2 sensor, it is less likely that it would cause any drivability problems anyway. Also, on most cars primary O2 sensors don't even have much if anything to do with wide open throttle fueling. Unfortunately, I have an S600 so I don't know enough about the S55 to give you any diagnostic advice as to what might be causing a whole bank to shut down.