I have a 2006 Cadillac STS-V (supercharged Northstar, not an LS engine
). One of my cats became suddenly clogged last night when I was accelerating on to the highway, causing the CEL to flash and the engine to bog down and sound terrible. I still had to drive it 100 more miles in this condition, though the CEL would only flash when I got on the gas and RPMs got high enough, further pointing to a clogged cat.
His morning, it finally threw an active code. I had it scanned and in fact got a P0420 and P0300, basically confirming the clogged cat.
I found a shop that happened to be open and was willing to gut my cats. With that now done, the car is 80% better, but still seems to suffer a slight loss of power. After driving around a bit, the only codes I have are 0420 and 0430, which are of course both expected.
So, my question is, what else could have happened as a result of driving for a few hours on a VERY clogged cat? Fouled plugs on that bank maybe?