Might try the fuel pump test jumper to see if that helps:
- http://www.4crawler.com/4x4/CheapTricks/index.shtml#FuelPump

And maybe check the fuel injector wire splices, several threads on that subject on this forum over the last few years. Might have a loose connection in one of the splices that is causing the running on 2 or 3 cylinders.