Alternator Kicks in At Idle.. Is this Normal..??

I noticed this ever since i had my 95 4.6, which is a good 5 months now. At idle, everything is fine, idle's around 750rpm. Now, i notice every couple minutes or so, i'll here a "tuck" noise from the engine area-it's very faint. Also when this happens, my rpms jump to just about 1000rpm's for like a second. Is that the alternator kicking in or what, i know the alt is constantly on. It's almost like the alt is re-generating for an instant causing this.

This happens when i'm in park, and just chillin for a little while drinkin my coffee (15mins or so).

probably the a/c pulley, mine does it too. get out and watch it some time, you'll see it.

The a/c kicking in would be my first thought. Next time you are drinking your coffee, turn off the air or just leave it on vent to see if it does the same thing.

i don't know about the 4.6's but if they got electric cooling fans, couldn't it just be that turning on?

I think that from the way he described it, its gotta be the a/c. totally normal.

Man do i feel like a retard.. It is infact the ac pulley. I always have it on panel/floor with the auto setting at 72 degrees. Today i noticed it, the auto feature basically turns the pulley on when the temp drops below 72, heats the cabin, turns off, turns on in a couple min's etc..

Thanks alot everyone.

hey speaking of that, whenever I put mine on auto, it just blows full blast. Its never worked properly for me, ever. I wish MY auto setting worked. ne ways.. my a/c pulley turns over every few minutes whether I have the a/c on or not.

Hey rick, no man, your auto feature is working correctly. What it does is this.. Let's say it's 50 degrees outside, you get in your car, and it's kinda cold, maybe like low 60's.. You put on your switch to either panel, or panel floor, whatever, set the degree (72 is good) then the auto feature warms up (or cools in summer) the inside of the car to the temp you have it at, then it stops. When the cars interior falls below the degree you set it to, it starts again blowing full blast to reach the set temp as fast as possible.

hmph.. maybe it does work. Ill have to check that out. thanks

hey guess what you were right. lol, ive had the car for over 2 years and never once used the auto feature cuz i thought it was messed up.. lol. oh well, I prefer adjusting it manually anyways.

Just an FYI, the a/c should not come on when in the control is in the floor or vent position, only in a/c norm, a/c max, defrost/defog, or panel/floor.

the pulley turning over is still normal though right? just like, one rotation every few minutes?