its a 98 cherokee 234000 miles full msd ignition.(if that matters) k so i checked it out and it sais (injector circuit) open= cylinder 1.... k so to strart with i had it runnin and pulled injector 1 plug no change, pulled injector 2 plug no change but 3 4 5 and 6 all made it run worst. its runnin like a lets just say it runs like a ford lol (no offence to ford guys) so i checked for power in the first two plugs and i have power... so i put two new injectors in and still the same thing cleared the code and it came on within 10 seconds..... so one thing i was told is im supposed to prime new injectors, i didnt do that. could that be it??? any ideas???

 

FSM says nothing about priming the injectors.

The injectors open when the PC compltes the ground path. Check the engine grounds and the grounds adjacent to the PCM.

 

x2, You could also check the wires between inj and pcm , ground/trigger side.