So I get back in the car to go home from my girlfriends house about... thirty minutes ago now. I crank it, it fires up... and it's making a whistling noise And the idle is all squirrely... it held at about 1200RPM for thirty seconds and then started slowly coming down to around 750RPM... still making the whistling sound. At first I freaked and thought it was the rear end but then I realized the car was still in park and nothing back there was turning...

Next thought... IAC (because of the stumbly idle) or the AIR pump. My mechanic told me the AIR pump was on the way out (screw pollution controls, right?) so I didn't know if maybe that was the noise.

Anybody have any clue? This is a 305, Tuned Port Injection.

 

My car was making a whistling noise too and all it was, was the AIR tube came off of the cat. You might want to check that out. After I did that the noise stopped and hasn't done it since..

 

i had a z that whisled so loud, people thought I had a supercharger under the hood. turns out my altenator was making this noise, i heard that this happens sometimes right before the altenator goes south.

 

mine makes the same whistling noise at the frnt of the engine, but goes away when the throttle is pushed. Does this sound like the same problems as above?

 

bad bearings in accessories will cause the idle to fluctuate because of the incrased resistance. My dud a/c compressor that im using for an idler pully causes this. Faint grind that coencides with the rpm fluctuations.

 

ya I didn't say before, but my rpm does fluctuate at idle. so I prolly have bad bearings in an accessory. Any way to tell which one is the prob?? Also does the increased resistance affect HP?

 

irradic idle and whisleing = vaccum leak (normally)

does it change pitch when you lightly press the gas?

If an accessory bearing were to have enough friction to cause irradic idle it would be VERY obvious which one it was!!

I was once trying to find a very low pitch moan with a scope, and just about the time I touched it to the ALT the rear bearing shot passed my head glowing red hot!! I almost pissed my pants!!

 

You should have heard mine the other day , it was whistling Andy Griffin .

 

Yes,

the pitch gets higher when the gas is pressed lightly. And returns to a lower pitch when let off the accel.

Does that give you an idea of what is is?

also, the idle is not so much erratic. Just a little low. I start the car and it goes to around 500-550rpm. After driving a minute it is at 750 though.

 

A trick that works quite well is to spray some dish soap/water solution in the center and backside of the accessory. Once you hit the right one it will quiet right down. Also don't forget the bearing in the back of the alternator. This trick solved this problem 3 times for me. A bad water pump bearing, a bad alternator bearing and also a bad idler pully (on my 2.8)

Once you find it, you can try shooting some PJ1 chain wax (for motorcycles) on it. Sometimes it keeps the noise away for quite some time.... But if a bearing is completely hashed......

 

well I would buy a $5 mechanics stephiscope and use it to narrow down your problem. Most auto parts have them.

good luck.

 

Turns out mine was the alternator bearing... gettin' a new one on Monday. Thanks for all the help!