I just noticed this today. Threre is a loud whistling when I am giving the car gas at part throttle. It is only there when the AC is on I believe. There always was a whistling but it was only at idle with the throttle at a certain point aNd could only hear it with the hood open. I just got my AC fixed Yesturday and the whistling just started today. I wonder if the shop messed with somethig else. The shop didn't replace anything but had to fix the wiring to the compressor. This is from my 89 2.8.

 

How daes the car run? Sounds like a vacuum leak to me, and when you have the A/C on there is more load on the motor, which means it needs more air/fuel, so the whistle becomes louder.

Other aptions are a slipping belt, bad tensioner bearing, bad A/C pulley bearing, or slipping A/C compressor clutch.

Best thing to do is open the hood and try to pinpoint the area of the whistle, it'll help a lot on the diag.

 

The car runs fine. I have to let it idle a little high. I swear I got all of the vaccum leaks. I have been chasing them for a while and found the last few that should be fixed. Idle is smooth to ~1100 and lower with the AC on. There was a little bit of a whistle that could be heard before but that was from the TB sucking up air. Now the whistle is under throttle so I don't know if I can pinpoint where it is comming from. I'll mess with it tommorrow afternoon.

 

1100 RPM is definitly too hihg an idle speed. Mine idles right at 750 the entire time, A/C on or off, doesn't matter. Unless you set the idle speed that high, there is definitly a leak somewhere.

 

I second that. Before i installed new injectors it bounced between 550-650rpm. now that i have them installed it sits at 550 dead smooth. I have whistling sound at part throttle but i believe its just my TB leaking.

 

I know that the idle is high and I am trying to figure that out. I have installed new injector o-rings, TPS, IAC, MAF, plugs, wires, and various vaccum lines. I am going to get a new cap here pretty seen and I need to test my fuel pressure. It doesn't matter what i do the engine always will die at ~1000.

 

my car starts at a high idle as well , 1200 or so then as it the engine warms up in drops to around 795 or something like that ...but then it will also drop to like 500 something and sound like its gonna die , only to go back to normal

 

vaccum leak. theres some lines right underneath the tb too, as you state its sounds like its comming from there.

 

last month i had a similar problem in my 91 3.1 Turned out to be the EGR valve blowing a small amount of exhaust gas out of one side where it bolts to the exhaust manifold. it would get louder with throttle because exhaust gases were faster. a new egr gasket did the trick

 

did you replace the intake gaskets when you pulled everything apart? This is important becuase we have paper gaskets that are not designed to be reused after they are compressed.

 

Yes all of the intake and EGR gaskets are replaced.