Is that on the d2 as well, I’m heading in next week for yet another 02 problem hoping new cats will help

 

Before you go tossing parts at it find out what is failing first. The engine running smooth and clean with all injectors flowing equally not parically clogged or of a crappy "squirt flow" pattern? I'm talking those 80's designed Lucas pieces of rubbish? What are your O2 voltage readings and are they cycling up and down the voltage scale or rather steady (flat line dead) engine running as well driving under variable loading in real time?
Hc & Co numbers AHEAD of the Cats checking the engine's fueling system if it's fueling properly?
If the intake snorkel is like the one on the 94 and 95 3.9 and your "4.0" which has the exact 3.9 litre displacement, that snorkel inlet diameter is too small plus it's sucking hot under hood heated engine air.
Must mention i'm a 95 D1 5 speed with a 4.6 engine that I flushed, checked flow pattern and flow checked a set of Bosch 4 hole injectors to within 3/4% variation between injectors. Fuel pressure regulator another POS even new hovering at the minium psi of factory spec. At least 94 and 95 D1 with their 2.5 BAR regulator that is identical physically as the 3.0 Bar regulators used on late 80's and newer BMW's which will bump the pressure up near LR's maximum psi numbers allowing for a finer more defined spray pattern. Resulting in slightly lower emissions, better running, quicker starts like by the second cylinder over compression cold starts your running. Your starter will thank you, a win win all around. The 94 and 95 being OB1 plus a distriubtor vs coil packs and computer controled advance, again rubbish in my book. I can tune to what the engine wants waking it up altering inital and advance curve plus total advance allowing improved overall running and power you can feel. Mark Adams chip that a big increase in performance by itself. Chip installed years ago that also passes Kakifornia's **** smog actually "TOO CLEAN" with the sniff test.
BTW, back in 2000 a month after ownership I removed about 80 pounds of useless rubbish called the Cat back exhaust system and installed a complete stainless systrem from Borla. Better flowing Cats and exhaust system a nice gain.

You would barf if you saw how bad the intake to heads port mismatch, it horrible and speaking politely here and another restriction. We must install a OB2 Cats on OB1 vehices, that BS started several years ago. They check the date of Cat manufacture if installed before the new law your good, passed the "visual inspection" part of test. No biggie for the other 47 or 49 states if allowed then go to Summit Racing , Jeg's or AutohausAZ. or any parts supplier for universal Cat replacements. The 94305, not a clue if they can be installed on the 96 OB2 Disco? Repalced as a pair having equal flow vs LR's flat and round which DO NOT fow equally the 9405's fit both in both sides. Between them installed and both old Cats 100% gutted out there is very little in flow restriction over OEM rubbish.
A secret here, even a newer 9405 Cat, remove the stainless heat shield and replace with one off the older "legal dated 94305 Cat" shield, bingo passes the visual inspection.
Last cats for a friend a couple years ago paid $92 each vs $87.

Sorry had an emergency to tend and now my thinking on this reply is all over the place, sorry. After wrenching on these engines going back to the 1960's era owned by GM I always had a soft spot for them. They can run "legally" on the street vs operating at speeds of a laded dump truck. Perfect would be a 5.0 litre build engine of 360-375 Hp, 380 Tq with good manors from off idle to 5,600 rpm's.....~~=o&o>.......

 

Inside a Cat cutaway;https://www.youtube.com/watch?v=ekQcy6GN1pM&ab_channel=WarpedPerception... ...~~=o&o>.......