Date registered: Oct 2003
Vehicle: 500SE AMG, E350 4matic, GL 450
Mentioned: 0 Post(s)
Quoted: 78 Post(s)
This could be a possibility as to what has happened. Note that I said "could". I am only theorizing. Your O2 sensor is bad so you are running rich. Combined with the cheap gas has caused damage to your catalytic converter. This would explain your multiple misfires. Not sure why cyl 2 did not misfire. A damage/clogged cat would explain your problem. If anyone feels I am incorrect, please chime in. I am sure Bugsy wants to get this fixed and get back on the road.
I would say that if your current course of action does not solve the problem, you can consider unbolting the exhaust system before the cat. Clear the CEL. See if this will let the engine run okay. Having not done this specifically to an R170, I have no idea how much work this is. I have removed cats before. Some were really easy, some were an unbelievable pain. You will know when you get under your car. Good luck.