I recently purchased a used Honda accord EX. When I run the car it idles fine (800-750rpm) but when I turn on the AC the Idle drops to about 200-300 rpm. I tested the Idle control valve and it works but as soon as I turn on the AC the idle drops almost instantly but at times it fluctuates back to normal for a second then back to the low idle. This only happens when I'm in drive or in park. Also, I can hear something turning on and off when the idle fluctuating. Plus the car rattles with RPM so badly the license plate shakes uncontrolable and I can feel it in the steering wheel. I cleaned out the intake system all tubes, hoses, throatle body but nothing. I did a tune up with NGK iridium plugs, wires, cap and rotor but nothing. I also recharged the AC with a do it yourself kit and it did get colder but still with the idle problem. AC works fine when driving and RPM is over 1500rpm but I can feel some lagging when the AC is on. Any Ideas to what is causing this?