Jay-D,

I've got the same car and had the same problem. After the car was thoroughly warmed up and while idling in hot weather with the A/C on, the warning lights would start to flicker randomly and the engine would stumble a little bit. When I turned off the A/C the problem would go away.

Between your battery and driver side headlight down on the body you will see a rack of slide on terminals with a bolt holding the rack to the car body. This is a ground point for all kinds of things on your car. I found that the bracket is mounted onto painted metal, thus relying on the bolt threads to give a good ground. I removed the bracket and cleaned everything thoroughly including all the little slide-on terminals. I then removed the paint from the raised boss on the car body with some sandpaper, and reattached the ground bar and covered the exposed metal with some anti-corrosion grease.

You'll need to remove the battery for access, but I haven't had a flicker since. I hope this works for you.