Background- Alternator replaced 2 yrs ago, battery 1 yr ago

Here's the deal, within the last week and a half, when slowing down to a stop, when I step on the clutch, the rpms are dropping down to 3-500 rpms for a like a brief moment when I stop and then they go back to normal. A couple of times I noticed the battery light come on for like a second then go off. The serpentine belt was making some noise so I replaced that figuring maybe there wasn't enough tension. Today I noticed the same thing happen and battery light come on twice and actually held for like two seconds then went off.

I dont know what to make of it. Maybe a dirty IAC valve??

BTW..all this seems to have started when the temps dropped to like 20 around here..

 

Clean the throttle body and IACV valve.
The battery light is coming on because the idle speed drops to low for the alternator to put out the correct voltage.

 

Makes sense. Thanks Tom! I had a sinking feeling that was it but I wasn't 100% sure. This is going to be fun to do in the freezing cold never mind the snowstorm!

 

Would it mean anything if the engine behaves this way in any weather, and does not produce a battery light?

 

Probably the same thing. I've seen people with the same issue and it turned out to be the IACV valve or TB as Tom mentioned. I had the battery light coming on in my case- which I had not seen with anyone else and that is what got me all ...

 

So, I cleaned both the IAC Valve and the TB. You cannot believe the dirt that was in there! If you haven't done this, do it, its not- that- hard. Definite improvement on the rpms- not going down to 3-500 rpm range. Its stabilized at about 800 rpms However, I'm still having the battery light come on when I do stop. I've noticed that this is happening at night when I have the lights on. The curious thing is, if I step off the brake pedal, the battery light goes off and does not come on. As soon as I step on it again, the darned thing lights up as if I'm doing a roll call! This would indicate to me that I'm still having some sort of a drain on the battery. Is this where I finally panic and go get a new alternator, 1.5 yrs after the last install??