I installed a Pro-jection system on my 360 J20 back in 1995. Within the 1st yr it had one of the two injectors go bad...acted somewhat like the issue here. The next year it had the fuel pump (electric came with the kit) fail. The last failure for anything was in 1997. It has run flawlessly ever since...nearly 20 yrs now and it sits in winter storage for 6 months of the year and never has gas additive put in the tank...fires up and with 6 month old gas goes to the nearest gas station and gets a tank of premium to start the season off.
Call me lucky from the sounds of it. It is an open loop system...no O2 sensor and is analog with the rheostat knobs on the ECM. Initial tuning does need to be done per the manual and that takes a copilot and a tach. with some nice open non busy road.
If you do need to replace the injectors, don't buy a holley unit,, it's the same part/performance as an injector for a Dodge Dakota 5.2L from around 1995-6 or so and much cheaper if you get one from a jobber ie NAPA/UAP under the Eclid name.
'82 J20, 360,TF727, NP 208, Holly Projection.'74 paint scheme
'67 Jeepster 8701,true convertible,TH400,pwr top,
'91 XJ, 4.0L,auto,Selectrac,Ramsey 8000,GC upcountry susp
'98 XJ, 4.0L,auto, Selectrac, police package