1990 Ford ranger 4.0 running rich, loss of power

I recently bought a 1990 Ford ranger with a 4.0 and
noticed the engine was missing, so I pulled all the
plugs and found the number two plug was fouled. I
went and bought all new plugs and wires and it
seems to be running better, after a few days I
popped the number two plug out again to check on
it and it's wet with oil, hence how it got fouled in
the first place. I notice the truck lacks power and
runs extremely rich and blows a blueish almost
white smoke out, the coolant levels are fine and
the oil is not milky so I'm not burning coolant. I
took out the maf sensor and took it apart and it
was visibly clean and in working order. I was
thinking maybe it had a valve problem but I'm not
sure, any input is appreciated.