ca86108

I couldn't pass smog forever, found out I had a bad cat. Honda is putting a new one in for me. I noticed that my ap2 felt slower than the ap1 i drove before, I was wondering if a cat can cause any difference in a loss of power? Would it be minimal or significat?

PWRMKR

forever? It depends on how bad the cat was. It might not have at first, but after some time, a disloged cat may start causing some blockage.
Tell us how it is after you drive with the new cat and sensor.

PerformancePackage

It depends on how the cat failed; if it's internally melted, or otherwise clogged with carbon deposits, it could be a serious exhaust restriction, and could greatly limit your power.

I assume the car is also throwing a CEL - in this case the ECU might be limiting power, or you could also have a dirty or non-working oxygen sensor, all of which could reduce performance.

SgtB

If the cat is bad it would throw a secondary o2 cel that doesn't effect power. A melted or rotated core will hurt performance.

05APdeuce

If it is plugged, Yes

fitfors2k

Extremely clogged cat can make it feel like your car doesn't want to go over 3000 rpms..... so yes a performance issue!