Leaky fuel injector(s).
left side of the fuel rail by the #1 injector.
ecm and ing. module
plugged up fuel injector or bad injector itself.
Inside the fuel tank, on the top.
If it is just one injector, it is a bad injector or a problem in the wiring harness or connector for that injector. If it is all of the injectors, it could be a fuse, the entire injector harness, a broken loose or unplugged connector on the injector harness, or the fuel pump or fuel pressure regulator.
A bad spark plug or spark plug wire can cause your engine to miss and lack power. A bad fuel injector or dirty fuel injector can also cause the problem.
The 1989 Ford Ranger fuel pressure regulator can be found on the top of the engine. The fuel pressure regulator will be behind the fuel injector pump.
On top of the moter , passenger side it has fuel line running to injector pump
Chandge the fuel filter first then try running some injector cleaner through it. If that doesn't work a mechanic will have to look at it.