Went to change back plugs and removed everything I coulod see to take off plastic air plenum. Lifts up from the front a minimal amount from intake manifold but feels like something is holding it in the back. Anybody familiar with what is holding back from removal? I disconnected all connectors, brace on throttle body, screws holding egr, all hoses and bolts holding plenum to intake.

Many Thanks and Best Regards Always, Robert

 

Not sure if they are set up the same, but on my 04 3.5 liter there was one stud at the back with a nut holding the back of the plenum in place.
It took me a few minutes to find it. look at the back, towards the center of the plenum. on the 04, it was under the throttle body.