Looks to be blown to me. That's what mine looked like

 

Is there any oil pooling anywhere ? Depending on mileage that might be just from the PCV. The "official" way to check the plenum gasket is to see if there's vacuum in the crankcase. In normal operation there's a slight pressure in the crankcase from blow by, vacuum means there is a passage to the intake a.k.a defective plenum gasket.

 

Looks normal to me but if original, should be done anyway.

 

If you look it starts getting a pool towards the right of the picture. It's had this odd misfire when you start it in the morning, runs rich as hell, and has a vacuum when you start it straight from down in the throttle body.

 

Its gotten progressively worse over time as well. I've replaced every single sensor including the pcm. It destroyed my cat as well

 

Truck only has 78k on it. I've been chasing this for a year now

 

My longterm fuel trim is -33.

 

it starts very odd in the morning. Suction noise like a vacuum leak. It misfires so bad it sounds cammed. Once warm it runs better but still rich as all hell. Cat is gutted since it got destroyed and my o2 keeps getting lazy.

 

Do a vacuum test and find out where the leak is. Or just dive in and replace the gasket. I had mine done preventively over 200k ago with the Hughes kit.