candu

Plugging up PCV orifice and line was causing idle surging on my ecotec3 5.3. Would go from 400-700 rpm every 3 seconds cycle. Turning AC on would drag this cycling lower. Some stutter and intermittent shake type vibration. Took the PCV connection apart on drivers side, mid point above the valve cover. Sprayed a few blasts of Brake & Parts Cleaner in both directions. Back together and started it. A couple of minutes of the surging, and then it settled in to steady 550 rpm. Turning AC on drops rpm to 500 for 2 seconds, then steady at 550. Be careful that you don't get too generous with the spraying. Better to do this procedure a few times than too much all at once. Carb Cleaner would work as well.