Btw, thanks for the help Ken and everyone else. I'll update as things move along

 

Wow, thats the ****ty manifold my XJ has? That looks horrible, and probably jack for aftermarket, and a ton of $$ to replace when those CATs go bad

 

Haha. Yeah it's not pretty

 

After doing some research, it appears this type does not suffer from the breaks and cracks at the collector, and they flow well. So no need for aftermarket or replacement.
If the CATs go bad, Ill just have them gutted and get some post CAT O2 sims or maybe try some sparkplug defoulers.

 

Generally we don't bring up deactivation of catalytic converters on this Forum.


Cat Laws:


https://www.cherokeeforum.com/f2/cat...er-laws-24337/

 

...and then add a single high flo further down the exhaust line

 

At least it's a relief to know those manifolds don't crack super easy.

 

The California emissions exhaust should have an unmonitored Cat downstream already.

 

Wow, 3 freaking CATs?! Crazy, tho I guess it doesn't matter, at 203k Im sure Ill need to replace it anyway. Not to mention it's ability to keep up if the front ones are removed.

 

*Update*

So after I pulled the manifolds, replaced the gasket, cleaned the living hell out of the intake (it was atrocious) and replaced the previously installed Bosch O2 for an NTK, I drove it about 12 miles. Ran awesome. Next day, CEL back on. Misfires like crazy.

Finally got it on a good scanner and saw that the upstream O2 in the rear would read normal one minute, then die, then read normal again. Figured there was a pinch or break in the wire, So we ran a new wire, bypassing the harness, and voila, runs great.

Btw, Initially had an O2 grounded to chassis code... I guess it pays to know what these codes actually mean. Live and learn.

Thanks for the help from everyone.