Tendency to stall

I have replaced all of the critical emissions sensors (because of an engine swap), and the idle air control valve (which have worked better). This XJ tends to stall when I hit a nasty bump - and luckily with good recovery. It has warmed up enough to prevent stalling while in motion, but I'm thinking that everything is pointing to the ECU.

What else should I look at?

Where the CPS plugs into the injector harness, the harness side of the connector, it makes sharp bend right there and has been known to fatigue through the wire, under the insulation. There was a TSB or infromation letter about this way back when. Inspect the CPS wire, it has been know to cook through and bounce around on the exhaust manifold.
Check the grounds at the dipstick holder.
Check the connectors and the spaghetti near the starter relay and the relay block.
Swap in another coil to cap wire. Or ohm test the coil to cap wire, while twisting it and bending it.
Other than that, I'd shake most every cable I could get my hands on (with the motor running) and see what happens. I inspect my cables and connectors often. And tie up (I keep a selection of cable ties and plastic cable armor handy) and out of the way most any cable I find rubbing someplace. Every time I do an inspection, I find a rub someplace. Don't forget about under the dash near the steering column and the brake pedal.

I had this exact same problem earlier this year. I too replaced every damn sensor on it and still had the problem. I finally removed the ECU box from under my dash. Took it out of the box and found about a tablespoon of water rolling around inside it. Must have been shorting out a few pins when it sloshed around.

I dried it out, sealed all the box joints with black RTV including the area where the main plug goes into the box. Used some di-electrical compound on the plug contacts and put it back in the Jeep.

Problem went away and has never returned so far.