stalling when idle

After a week install of my stereo system with the battery being disconnected all week my car seems to have a problem when idling.
The car runs fine, it drives perfectly but today if i left it idle for a while the rpms would drop and the car would just shut off. Also my rpms seem to be fluctuating at idle. I also went to buy a new battery and the guy checked it and told me it was perfectly fine. I have no idea what to do is it possible that the computer needs to relearn still. Its been 3 days since i have started the car and have been using it.

clean the throttle body.

better yet, do a search on this website. youll probably find 2 dozen questions just like yours.

check your MAS. sounds exactly like what my g did a few years ago. intake wasn't tightened good, and it would fluctuate at idle. might wanna add a ground to your engine also. but i dunno if it really has anything to do with your stereo....

I Had the same problem after installing my stereo, come to find out that I blew a fuse (10amp) under the hood the ones you have to pull up.

i blew a fuse after my install too, but my RPM wasn't affected. i would just lose everything controlled by that fuse, but ya never know, could be a different fuse. so yeah, give that a look too.

Is the 1100 watts RMS too much for the 85 amp alternator with stock battery. I plan on getting a yellow top very soon.

HELLO!
I just gave you the answer.
clean your throttle body.

yeah, don't listen to anyone else, go check out your TB and let us know how the car runs.

Brought the car into my best friends dad, a mechanic. Cleaned the throttle body, ran electrical diagnostics and changed my alternator belts for $55. Car runs excellent turns out that when i bought the car the over compensated for the dirty tb so after it was cleaned the idle was like 1500. Its all good now and tomorrow he will be installing a nice optima yellow top battery. Thanks for the suggestions its exactly what had to be done.

Nice conviction, Manybrews! and the truth shall set you free...