Intake manifold leak

I have a 93 f 150 w/ a 5.8 lt in it I was wondering if i have a intake leak. When I take out my spark plugs I can smell gas/oil mix. Would that be a simple fix or would it be something more complex?

more likely a leaking fuel pressure regulator or some injectors or bad sensors causing it to run very rich

Well, have you changed your oxygen sensors yet? I change mine every 80K. Try some new plugs, new upstream oxygen sensors ( before the convertor ), change your fuel filter, run some good injector cleaner (seafoam or Marvels mystery oil) and give it a shot. If your o2 sensors are bad, they will get carbon build up on them, and not read the correct oxygen reading, usually not enough oxygen, so the PCM module will richen the motor up.