Partially clogged cat?
 

Based on my research, I think I might have a partially clogged catalytic converter, but want to get the opinions of more experienced users.

Backstory:

06 Shinka with 26,700 Miles, 1 track day and 2 autox's while in my ownership. No engine mods other than K&N drop in filter. Oil changes done every 5K miles, premixing at fillups.

About 2 weeks ago while driving I would get hints of a sulfuric smell when coming to a stoplight/pulling away from a stop light. Could never tell if it was my car or the car infront of me.

Last week on the way home from work I noticed that my gear changes were exceptionally smooth--much smoother than I have ever been able to do, consistently. I also suspected a loss in power, but wasn't sure.

This weekend I drove up to the mountains and definitely feel a loss of power across the entire RPM range. I can no longer feel the variable intake ports opening like I used to. 3rd and 4th gear acceleration is reduced from normal.

Final symptom is a ticking noise associated with RPM on a cold start that was never there before. Noticed this the day after I noticed the gear changes.

I am taking it to the dealership tomorrow to have them check it over, but I feel like it is a partially clogged cat since I am not having cold/hot start issues, no idle issues, and no misfires.

Thoughts?

Thanks!

check spark plugs first, check coils second, check cat third