Hello gang,
So today I took the car for a nice long ride. Turns out the car was yelling at me for sitting in the garage for a while with a check engine light. Had the local dealer read my the codes and tell me it was catalytic converter related. In addition, I remember at one point smelling a strong sulfur smell in the car, classical "rotten eggs smell" which I know to occur when fuel is dumped on the catalytic converter. The dealer cleared the code, and it has not reappeared yet, however I think this was related to the drive I had today. Before I left, there was some rain, and the roads were all wet and slippery. I think at the point of the strong sulfur smell, some of the water got kicked up and got onto the coil, which in turn did not allow the spark plug to generate a spark, and fuel was dumped onto the cats. Few miles down the road, the computer realizes the cats are not working as intended and throws me a solid (NOT FLASHING) CEL. So, it would be safe to assume, I need to change my spark plugs and coils, and continue enjoying the car, rather than losing sleep over it. Please correct me if my line of thinking is wrong.

FYI, Iv had a similar crack coil problem on a previous 2003 911 Carrera.

 

If the CEL was for catalyst then I would think this has nothing to do with plugs, coils or wet weather. It will typically take several drives after clearing an emissions code for the smog diagnostics to run and determine if the original problem still exists. These cars seem to devour catalyst after 10 years / 50k miles.

 

Happens to me pretty regularly on long drives, even with freshly replaced cats. I carry a cheap code reader with me so I can check/clear the codes when the CEL comes back on. I still want to try a spacer for the downstream O2 sensor to see if that resolves it permanently.