I'm pretty sure all cylinders are firing but, that's easy enough to check.
The original Cat didn't fail and I still have it. I just replaced the cat and muffler because it was so old and I was trying to increase my milage.


1993 4Runner SR-5 4WD V-6 Auto Trans
1990 Pick-up (Hilux) 2WD SR-5 V-6 Auto Trans