[ActorMike]

I bought my 2012 Mustang last March it runs and idles great. Recently I removed factory throttle body and cleaned it with TB cleaner. It looked pretty dirty to me! I changed the spark plugs too, and they seemed really bad too! There was quite a bit of oil residue on the intake manifold too, you can see it in the photos as well, cleaned off the cover really good and also the top of the intake as much as possible.
I could obviously tell a different in response after changing the plugs.

 

[40th GT]

Is the car modified at all? What kind of fuel are you running? Your engine may be a good candidate for a air/oil separator.

 

[az.dsrt]

How many miles?

 

[fordpro]

That's pretty gunk!