First off its 94, 4.0L V6 Ford Ranger (daily driver). I've got some guys helping me out on a Ranger board but I figured I should consult the real experts.

So in theory what could cause this problem to occur?

The passenger side bank of cylinders is running rich where the drivers side is fine making the truck virtually undriveable.

Any thoughts are greatly appreciated
Thanks
Jason

Are you sure it is running rich or is it oil? Sometimes the smoke from one side of the engine (or dark plugs) means that there is a leak around the pistons or the valve guids are shot.

I went through the same thing and found the guides were gone.

first things first what makes you think its rich? O2 sensor reading do you have a gas anylyzer?
If it trully is rich My bet is the Fuel pressure regulator burst and its running raw fule in that side. Just pull the vacuum hose off the fuel pressure regulator and see if the problem stops. Good luck Paul