ok when i start my car everything is fine. it will run fine til it starts to get to operating temp then the idle will drop down between 5-650 RPMs. Also when i put on my breaks, the idle drops some. basically when extra electronics are used, the idle dies down and somtimes after letting off at high RPMs the rpms will drop down too fast and the car will die. sound like a bad alt?
if so, i heard the ka alt can bolt up, is that true?

Doesn't sound like a bad alternator to me. Remove the neg cable from your battery while it's running. If it dies, then it's probably the alt.

Check to be sure all your connectors are on tight. The engine will die and not start back up if it doesn't receive a water temp signal (mine slipped off while I was driving.. bad connector), so be sure it isn't on the verge of popping off.

As far as a KA alt bolting up, you just have to drill out the top hole. My Silvia alt was dead when I got it, and my KA alt charges the SR electronics perfectly. Don't make it too big.. just enough to fit the stock KA alt belt adjuster bolt. If it's too big, it's more likely to rattle and you'll be tightening your alt belt a lot.

actually i found out im running on two cylinders, that would cause my probs.
thanks ***,