High-pitched noise

[SVXplorer]

I took my car (the black one) for an oil change today. When it was done, fired the car up, and it immediately started making a high-pitched noise, coming from under the hood on the passenger side. It sounded like air escaping through a tiny hole at high velocity. The lube techs and I had a quick look under the hood, but we weren't able to locate the source of the noise. It's definitely not belts.

Any suggestions?

Also, on a possibly related note, my car was idling rough on braking yesterday. The rpms were fluctuating between 800 and just above 500. I thought it was because of low fuel, so I gassed up, but the problem didn't stop. Later, the car stalled once in the parking lot at work. So, I dumped in a bottle of CD-2 Super concentrated fuel injector cleaner, and the rough idle seems to have stopped. I was going to get the fuel filter done with the oil change today, but they didn't have one in stock (just as well, since the lube monkeys couldn't find the fuel filter on the car ).

[oab_au]

It could well be a vacuum leak from a broken or detached hose. As they have just done a oil change, they may have knocked a hose off. The likely one is the vacuum hose that runs from the right hand, back corner, of the inlet manifold, down to the fuel pressure regulator, when they checked the front diff oil level.

You can trace the sound, using a piece of hose as a stethoscope, to find where the sound is coming from.

Harvey.

[SVXplorer]

Thanks for the suggestion.

I checked the visible hoses, and I couldn't see anything out of place. So I took it back to the lube shop to see if they could find anything. They couldn't see anything disconnected or visibly cracked. But then I noticed that the bolts on the intake manifold were extremely loose, as in I could unscrew them with my fingers! So I bolted it back down (no torque wrench, though. It will have to wait for Nemesis Destiny to finish moving), and the sound went away!

I hope it stays gone.

On a bad note, the car stalled again as I was braking (this was before the air leak was fixed), so if the stalling continues, I guess I'll have a new thread to start.