I never really ended up finding out the problem, however I was told it was most likely the Intake Manifold gasket...

I replaced quite a bit that DIDNT fix it...i.e..Fuel Pressure Regulator, Fuel Filter, Plugs, wires, cap button, Cleaned EGR system, tested all sensors..

I sold the car right after I got it, but I do believe after all the research I did, the problem was air entering the IM from another place, instead of just from the intake. So my logical conclusion was air must be entering from the gasket sealing the intake manifold...

Hope I helped a bit.