So I had a misfire on 2 cylinders and the O2 sensors were trash. Changed the plugs,wires, cap, rotor, ignition coil and all 3 o2 sensors. Now I have a misfire on cylinder 6 and an evap code. Am I wrong in thinking my cat is toast? No smell, but bogs down a bit when I first get moving and runs a little rough. I want to get it mechanically sound before I start building it up. Only has 131k miles on it and a 2000 2 door 4x4.

 

Cyl 6 misfire and evap doesn't make me think of a bad cat. There is a code for low catalyst efficiency, that's the code you would see for a bad cat

 

You can test the exhaust back pressure in front of the cat using an O2 sensor port and/or shoot a few spots with sn IR temp gun to see what's going on

George

 

A misfire might be also related to a fuel pump problems, so You may want to test the fuel pressure too. It's in a sticky topic.

 

How did the plugs look?
Especially in the cylinders that were misfiring?

Also did you use AC Delco for Cap/Rotor replacement?
These engines are picky about ignition parts.

I had a off brand Dist cap crossfiring underneath years ago.
Caused all kinds of problems, ACDELCO all the way

Do a fuel pressure bleed down test