Well, so driving my Supra around lately, I had noticed that when I was stopped and idling, sometimes the idle would go below 500ish and the car would struggle and die if i didnt hold my foot on the gas a little bit. The battery being as old as it was, I went and replaced with a yellow top. Well, coming home, both the positive and negative terminals popped off and the car died. I went back, reconnected them, and started to drive the car around, but I noticed that now, the car wouldnt even try to idle, if i let my foot off the gas, RPMs would just continue to drop till zero. Assuming it was because the car lost power while in motion, I disconnected the battery and EFI fuses for a few mins. This seemed to work, but the car still idled very low and now it was back to the original problem of idling and sometimes dying if I didnt slightly keep my foot on the gas. That night, I was out driving and noticed that if i hit the brakes, or even hit the window switches, my headlights and all interior lights would dim very low; the headlights almost seemed to blink when I hit the brakes. Well, i bought new connectors for the battery cables so they wouldnt pop off again, and the car hasn't fallen flat on it's face like it did before, but, when warmed up, it will idle very low (500-480) and sometimes, will falter and try to die. When revved up to about 1000 rpm, however everything electrical seems fine. Seemed to me like an alternator issue, but I just wanted to check it out to make sure it's not something else.