Originally Posted by VEGAS
not mentioned here but just so you know it is just in the 2.3L, so 2.0L does not have the Flaps
Both the 20 & 23 use imrc= aka Tumble flaps. The 23 also has imrc similar to SVT's, but is vacum controlled instead of electric motor controlled as SVT's. The only manifold that doesn't have tumble flaps are the escape manifolds. Why I have no idea. There are threads all 'bout this, hit up the search. Lots & lots of great info.