Re: 1986 Ranger running too rich
Here is one possibility as it happened to my '86: there is a fuel pressure regulator that is vacuum powered on the left side (facing front) that reduces the pressure from the pump (around 90psi!). Mine had a bad diaphragm and two things were happening-the pressure overwhelmed the injectors forcing too much gas into the cyls, and the broken diaphragm allowed raw gas to be sucked into the crankcase through the vacuum line.
So check the pressure on the fuel rail-I think it should be less that 30 psi, but I don't remember for sure- I no longer have those shop manuals.
Also look (and smell) the oil! It may be contaminated with fuel, both from the vacuum line and the extra gas leaking past the piston rings into the crankcase. Be sure to change oil in either case once you have corrected the problem. Too rich running engines can have the oil contaminated no matter what the cause.