engine idle high in park , and sometimes in drive

my toyota 4 runner started idling high in park for several weeks, then it also started doing it in drive, made car when driving speed forward, not always but every now and then, but the high idle at about 2400 rpm is constant now. have changed every sensor almost, changed air mass flow, cleaned everything, check hoses, just stumped at how to fix it, only codes it shows is coolant temp sensor ( did change the radiator about 2 months before this started ) but does not seem like that would have to do with idle, could it be the computer ??
frustrated, i dont have anyone to help me with this, single disabled woman. HELP PLEASE !!