So, my buddy and I put our second 99 motor into an 88 xj, everything went swell, everything is buttoned up and happy, but its running like a paraplegic (no offense). Cps, tps, map all verified good, grounds refreshed, timing triple checked, firing order checked....only thing left that we may think it is is the gas that's in it.
Backstory:
Friend of a friend bought this auto 4x4 88 renix without a motor. For all we know, it s been in the field he bought it from for the past 4 years without a motor in it. It starts, idles, and all is happy. Put it gear, it creeps forwards and reverse, but if you give it any gas, she dies out. In park/neutral, you can rev it slowly to about 2500 rpm, before the motor has definite misses. Only thing we can think of is either fuel pressure, quality, or flow. We are going to test pressure tomorrow, along with fresh gas and filter, and some alcohol in the tank to try and dry up any water/contaminants.

Sensors used-
Renix tps adapted to 99 Tb
Ho map
Ho iac
Ho cts, iat
Renix dizzy, Cps, flywheel/flex plate
C101 refreshed

Tps has been adjusted per renix standards

If you havent yet, check fuel pressure. I do believe the 99 ho runs a higher pressure than the renix. May need to swap in a newer fuel pump.

Did you index the dizzy properly using a cut up cap?

I did a motor swap in my 91 and I played hell trying to get the distributer in proper position. Was my first swap and after it was timed properly she ran like a champ. Good thing to double check.

Yes. Tips 12 and 13 in my pink link below.

Distributor was off by one tooth, so it runs much smoother now. Turns out the fuel line (rubber) was disintegrated in the tank and it was sucking air most of the time. Any who, this was our second swap keeping the renix running system with a 99 motor, did it to mine prior, but mine wasn't in a field for 3 years either lol

Yep, took the old cap and cut it up for future use, something I've been needing to do for ages