Fluttering/Rattle noise....?

Hi, I have a '99 cavalier with a 2.2 SFI engine and ever since I've bought it used I hear a fluttering kind of noise coming from the passenger's side of the engine when I initially give it gas and it seems to be more amplified if the compressor is on (either A/C or the defrost). However after initial acceleration, you can not hear the noise. It's only apparent when you're idling in gear or initially give it gas in gear (drive or reverse). I thought it was the belt tensioner but I replaced that and it seemed to have helped some but the noise is still there. I was told I may just need a new belt as this one may have became too stretched, allowing the belt tensioner to sit in the relaxed state with the engine off. I know the lower (dog bone) mount needs replaced soon too but I don't think that's the cause of the noise. I also plan on replacing the plugs and wires at the same time as the belt and mount. Although if those things (belt and mount) do not help eliminate the noise, what do you think it could be? The bearing doesn't seem bad on the alternator when spinning it by hand with the belt off but I was wondering if it's more likely another pulley/bearing problem?

Also I might add that I notice at night when I come to a stop my headlights kind of 'flicker' a little WITHOUT the compressor (A/C or defrost) on and it's even more apparent obviously with the compressor on. I don't think this is normal and may be related to the noise I'm hearing? Your suggestions/input would be appreciated. Thanks.

A stretched belt can make noise, so can just about everything else you plan on replacing.

It's very hard to diagnose a sound over the internet. You'll need to either record it and post it, or listen around using a stethoscope (a long handled screwdriver will work too). Might have to do both.

A stretched belt can make noise, so can just about everything else you plan on replacing.

It's very hard to diagnose a sound over the internet. You'll need to either record it and post it, or listen around using a stethoscope (a long handled screwdriver will work too). Might have to do both.

Alright, I will go ahead a replace all the above as soon as I can get around to it and see if that doesn't help. If it's still making the noise and the lights are still dimming then I'll try to record it if I can. Thanks.