[Brian in Tucson]

I have the same problem. Done the same things. Figure I need to pull the intake manifolds off, replace a stripped screw and the vent hose that goes to the AOS (the expensive hose,) and seal it up really well.

Carb or brake clean won't help you localize any vacuum leaks. Starting fluid will, just use short shots, don't go crazy. or a handheld small unlit propane torch. Either will change the rpms when sucked in thru a leak.