The lower intake boot often cracks. See jfoj's sig file for help with vac hoses. There is a vac diagram under the hood too that might help.
TB gets stuck so that can be cleaned too while cleaning the icv.
I don't know your mileage (which helps to know), but assuming it's like most cars here, there might be a number of other basic items not maintained--plugs, filters, belts, pulleys--but rather than guess, if you haven't done so yet, get your codes read and search for them here...add them to this thread. They'll help point you in some direction...hopefully the right one. Autozone reads them for free.
Last edited by dmax; 01-28-2013 at 06:10 AM.