Oil Coating Inside Upper Intake

[Lubecktech]

I have a 1999 Explorer with 156k miles that has starter running poorly over the past month. It seems to have low engine power and misses. I was getting codes P0174 and P0306 and P0305 (miss on cyl. 5 & 6) plus a gasoline odor frequently when the engine was running. I replaced the plugs, wires. coil pack and upper intake manifold gaskets. When I removed the upper intake I found an oily coating on it's interior and on the interior of the first 2 sets of ports of the lower manifold. The set of ports closest to the firewall didn't look too bad. Is this normal or do I have a valve problem?? I will try to post a picture. The plugs are not fouled. Is it possible the crap I see has gotten the injectors dirty? The gasoline odor and code P0174 have gone away but not the poor performance and missing.

 

[IZwack]

In general, that's expected because of the crank case venting:

 

[Lubecktech]

Since that is normal is it possible having my fuel injectors cleaned at someplace like sears possibly help my problem?

 

[ThePhoenix]

maybe replace your pcv valve first...ya know..