My wifes 94 XJ 2wd 4.0 auto has been stalling and bucking. I figured ignition or something. Starts losing power and dying usually at speed. I have a running XJ that i have been swapping parts with. So far I've replaced dist./cap,rotor, coil,wires,cps,Tps,iacv,fuel filter,map,pcm,catalytic...