Rpms drop with ac on over 60 mph

[Dhoneyc1]

Hello everyone. I have an 06 Taurus that when the ac is on and I drive over 60 the rpms will drop from 2300 to 500 then jump back up. I tested the car by driving 65 and NOT running the ac and the car was fine. I can drive with the ac on and stay under 60 with no issues. When I turn the ac off this also will cause the rpms to drop to 500 for about 5 seconds and the engine feels like its going to stall. I looked at other similar ac /rpm issues my mine is effected more by speed than anything else. I'm getting ready to make a 1300 mile trip in the car and would appreciate all feedback.
Thanks again

 

[jrohner]

Electrical problem such as a bad ground maybe.

 

[Dhoneyc1]

Thanks guys. I just replaced the battery and have been driving without the ac on and it's running normal. The minute I turn on the ac and hit 60 plus it does it again. I'll have the electrical tested if I can

 

[dUo-sx]

always test your battery before buying new, youll save yourself alot of money this way and with other things as well. forums are nice because they give suggestions but we cant obviously be exactly spot on when we cant see the car, keep this in mind.

Rpms going down when ac is turned on is normal but the drop is usually only a couple hundred rpms. So have your alternator checked it may be very weak or going out, but also it could be your idle solenoid. gl