[99monster stang]

Hello everyone, im pretty new to this so bear with me. I have a 1999 mustang, 100k miles, and recently about 1-3 seconds after i turn the car off the is a loud squealing noise, such as a baloon if you pulledd the end of a baloon with your two fingers. Ive been told it may be a vaccum leak but im not sure. Also, if this may be a symptom, it has a very bad idle, it will go to 1200, then down to 500 where it wants to die, and also the is a strong exhaust smell. Your help will be greatly apprecieated, this crap is so annoying everytime i turn her off :yelpleased:

 

[99monster stang]

I forgot to say that the mods are a K&N intake, flowmater exhausts, and just ordered a BBK throttle body....Also, a ford mechanic told me it could be the MAF, IAC, TPS, or spark plug wires, but thats kind of broad

 

[Joel85stangcoup]

Sounds like a vacuum leak to me, Listen under the hood to see if you pin point where it is leaking (while it is running).

 

[99monster stang]

Alight ill check,and i guess if i spray the hoses with throttle cleaner and it hits the leak ill hear my rpm jump? I think ill stop by autozone and see if i have any luck

 

[wmburns]

The noise happens AFTER you turn the car off? Does it happen if the AC is off?

Have you looked at the cooling fan as a possible source of this noise?

I just don't see the noise as a vacuum leak. The engine vacuum very quickly goes to zero after shutdown. I don't see the motor maintaining vacuum for even a second after shutdown. For the noise to be a vacuum leak, it should be there while the motor is running as well.

Please post all DTC codes.

The idle problem may be a separate issue. Check out:

http://www.allfordmustangs.com/foru...-dieing-idle-idling-rough-14.html#post2260649

 

[99monster stang]

Yes, sometimes right when the engine is turned off, or a couple seconds after it will make that sound, and im not sure like you said, the idle could be a whole other problem, so im tring to figure out thwat thesr two problems are. As for a/c, i barley ever use it, im a windows down guy lol...and the sound seems to come from the top left side of the engine, where all the hoses and wires are. Im going to autozone in a couple house to get throttle cleaner, ill inspect all the hoses and spray iffy ones and see if i get a response. If i get nothin ill try to post a video so you can hear what im talking about, sounds extremely wierd :?: and what are DTC codes? sorry im new to this

 

[wmburns]

Perhaps a leaking fuel injector (fuel pressure leak down). That would explain the fuel smell as well.

Try using a mechanic's stethoscope on each fuel injector.

DTC=Diagnostic trouble code, aka=check engine light.

 

[99monster stang]

hmm that sounds very possible, ill check it out...and as far as the check engine lights, there is none, nothing comes up or shows a problem, just the loud squeal, rough idling, and the fuel smell but i guess it doesnt trigger the light...but ill try what you said about the fuel injectors

 

[99monster stang]

Ok you guys are going to laugh....so i had my first day off that i could really go through the car. I deccided to clean my CAI filter, so i bought the kit and popped off the filter...holy crap! It was literally straight rust! :nogrinner The previous owner must have never cleaned it, but it doesnt end there, the metal claps that hold it down was put on wrong!He put it on an angle so only half was actually air sealed down, the other side was wide open! Then i decide to check the rest of the CAI and what do you know, 2 couplings with only half on the intake pipes, just like the clamp, it was sealed at the top and wide open at the bottom, i actually was able to stick my finger into the intake pipe from the couplings gap! So i went through it all, fixed all the seals, put a new filter on and boy does she feel better. My idling problem is gone aswell as the squeal!