2007 with about 170,000 miles. Has been great vehicle. Had developed slightly high idle speed, 1000-1200 rpm. Removed and cleaned throttle body and did idle relearn. Idle about 9500-950 rom. Noticed throttle plate not closed tight even when off vehicle. Has started slow return to idle when take foot off throttle from when driving. This has the electronic idle air control. How or can I clean this or dismantle without damage to see why throttle sticking? Or other suggestions. Car starts promptly and idles smooth, just slightly high.