So I'm having a little trouble diagnosing this one I'm pretty sure it's a clogged catalytic converter but would like to know what you all think. I know the p0300 is in cylinder 3, 5, and 7 with cylinder 7 having the most misfires. When I try to accelerate quickly there's a rumbling/muffled sound and when I get to 40mph the check engine light starts flashing and it's like I have a lose of power and doesn't want to go over 40mph followed by some popping/bogging feeling but not like a loud backfire. When I'm in drive and come to a stop if feels like it's bogging and wants to Stahl I also have a strong rotten egg/sulfur smell. I've replaced o2 sensors and cleaned the fuel injectors any opinions or advice would be much appreciated!