`92 XJ Runs Rough Above 1500RPM

I have a `92 XJ 4X4 Automatic , 4.0. It had a no start and threw a 54 code (No sync signal). I replaced the distributor , cap, rotor, wires (all from Oreilly), and plugs. It starts and idles beautifully, but when the RPMs reach 1500 on acceleration, it starts to run rough, backfires through the throttle body, etc. I installed the distributor per the shop manual . Im not sure if I have a bad distributor or if I didnt install it correctly. The rotor lines up with the #1 plug position on the cap (5 oclock as stated in the FSM). Thanks for any help- I`m stumped.

It sounds like you're a tooth off. At top dead center the rotor should have just past the #1 position. Because it fires the spark plug well before top dead center.