Recently rebuilt a 2.3L in my 1988 Ranger. When I time it to factory specifications, it has little to no throttle response, I advance the timing slightly, it increases the idle rpm but seems to accelerate fine. But looking at the plugs, it is running very rich. During the rebuild we replaced the injectors and the fuel pressure regulator. I verified that the new injectors are the correct ones. Just stumped at this point!

Any help would be appreciated.