Originally Posted by 400Kranger
I have a 1991 Ranger with a 2.9 l engine. The problem I have started around 2 weeks after I replaced a bad fuel pump. It will start, after I crank it for a while and after it begins to fire, I pump the accelerator to keep it going. If I let up on it, it will idle down rapidly and sit there running like it is hitting on 2 or 3 cylinders and then die. If I remove the hose from the intake manifold and spray starting fluid into it, it will start and run perfectly until the starting fluid is used up.
Since it responds to starter fluid, I would guess:
Vacuum leak; or
Low fuel pressure while running
I'm not sure but I suspect that your engine is speed density, bank-to-bank injection. If so, that opens up a couple more good possibilities:
Open PCM injector wire to one cylinder bank (actuates 3 of the 6 injectors); or
Bad Manifold Absolute Pressure (MAP) sensor