Question...is there a gasket between the air intake and the throttle body (the parts you opened up to get to the egr ports), or are the surfaces just metal and bolted together? I'd like to know prior to opening this thing up. I've got a 2002 w/65k miles, 2.5L with the CEL giving me a PO400 as well as failure readings on both o2 sensors. I'm hoping the fix is as easy as this.