I have a '94 mazda mx3 , and my problem is when i turn on my accessories,heat/air,rear defrost,etc. my idle bounces from 800 rpm's to say 1600 rpm's.But it only happens when i apply the brakes to come to a stop.I am assuming electrical;like charging or a ground,but any suggestions would be nice.please let me know what you think.Thank you.

 

have you checked the battery and alternator