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Problem with check engine light and strange engine noise
I have a 2000 Ford Mustang 3.8L V6 and I am having problems with it. I get a check engine light on when it runs for a long period of time and don't know why. I get engine running too lean codes on it. The obd II sensor says the sensors from all systems are ok, and I just changed the fuel filter. Also, when the engine is warmed up all the way, when idle, it first starts squeaking then it starts whining and wailing. When I turn off the engine, I hear what sounds like air escaping, but not sure. Can anyone help me? I love my mustang and hope it's not something too serious.
Hello,
What Exact Codes are You Getting? Does your reader Check Fuel Trims?
The Whining & Wailing Sounds Like Air Bypass Valve. It Controls Idle Speed. You Also may have a Vacuum Leak & Need to Check all Vacuum Hoses to Start. Get a Helper under the Hood at Shut Off & Try & Pin Down Sound. Shut Off Sound Could Be A/C System if you are Using It Currently. It's All Process of Elimination.
KC
Air Bypass Pic For You! By Throttle Body.
Last edited by 05stangkc; Aug 2, 2022 at 03:23 PM.
Hello,
What Exact Codes are You Getting? Does your reader Check Fuel Trims?
The Whining & Wailing Sounds Like Air Bypass Valve. It Controls Idle Speed. You Also may have a Vacuum Leak & Need to Check all Vacuum Hoses to Start. Get a Helper under the Hood at Shut Off & Try & Pin Down Sound. Shut Off Sound Could Be A/C System if you are Using It Currently. It's All Process of Elimination.
KC
Air Bypass Pic For You! By Throttle Body.
I am getting either a P0171 or a P0174 or sometimes both. They usually only come on when the car has been run for a while after warming up all the way. Could the air bypass valve also cause this? The whining only happens when the car warms up completely. A/C system I don't use.
When the Car is Cold it is in Rich Mode Per Say and Once it Warms Up Then the Lean Issue gets Compounded. I had the Same Codes on my 02 Harley F150 Supercharged and Chased it a couple of Times!
First time it was a Bad PCV Line which on the Harley Truck you got to pull the Blower to replace. Fixed it For awhile until the next Time Then it Turned out to be a Leak Between the Exhaust Manifold & Head Pipe which you could only Hear Going Down a Narrow Road with tall buildings on both sides so you could hear the Echo. A PIT PIT PIT Sound. Exhaust Leaks Reek Havoc on the 02'sensors.
Fords Are notorious also for the Vacuum Lines turning to Mush. You Grab Certain Ones and they Turn to Goo! Had to Replace the EGR Transducer Lines for what would have been a Vacuum Leak. If you grab a Vacuum Line and You hands are covered in a Sooty mess those lines need attention.
The Whining Wailing I have heard over the Years when an Air Bypass Goes Bad, But Unsure if a Failed one would Throw Lean Codes. You Should be able to Feel the Valve Pulsate When The Noise Occurs if it has Issues. Failed Air Bypass would Likely Give Poor Idling Too High, Too Low or Surging.
I was in Ford Dealership Parts for 35+ Years & have Picked up some Knowledge but I'm no Line Tech I Just Worked & Learned from Them, I always advise Checking things out First vs Just throwing Parts at it as Some Do.
Hope this gives you a starting point!
KC
Last edited by 05stangkc; Aug 2, 2022 at 04:50 PM.
Nope. Cleaning it didn't do much about the noise, but the check engine light hasn't come on yet. I ordered a new IAC part, so I'll see if I can do something about that. Also, the inside has what looks like black sludge. What do you recommend to clean it out with?
Should I just use a rag to clean the black sludge inside the engine where the throttle body and IAC are attached? Or is there something you can recommend?
Should I just use a rag to clean the black sludge inside the engine where the throttle body and IAC are attached? Or is there something you can recommend?
A Good Spray Throttle Body Cleaner Use a Namebrand Like CRC Etc. Don't Use Quote Carb Only Cleaner. Should Specify T/b or T/b and Carb. If you Clean Off Vehicle Get The Gaskets You Will Need Before Hand.
SUPERCHARGED RED ROCKET ------------------Master-Moderator
Joined: May 11, 2006
Posts: 10,648
Likes: 2,514
From: Carnegie, PA
If the MAF sensor has a malfunction, it most definitely is a contributing factor... First step, is use CRC MAF sensor cleaner... If this doesn't help resolve your issue, then I would look into replacing the MAF sensor...
SUPERCHARGED RED ROCKET ------------------Master-Moderator
Joined: May 11, 2006
Posts: 10,648
Likes: 2,514
From: Carnegie, PA
Check the code for long term fuel trim on google.. The description will say whether it's related to a faulty 02 sensor, or if it's related to something else
It was my O2 sensors. The 2 on my engine went, and the two on my converters were trying to compensate. When I got them replaced, the mechanic didn't burn off the stuff that they put on. That also sometimes trips the check engine light. Do I have to just keep driving until I burn it off?
It was my O2 sensors. The 2 on my engine went, and the two on my converters were trying to compensate. When I got them replaced, the mechanic didn't burn off the stuff that they put on. That also sometimes trips the check engine light. Do I have to just keep driving until I burn it off?
I would Pull it and Spray It Down with an 02 Friendly Cleaner! Check Wiring Carefully as Well While you are At It! New Parts Can Be Bad out of the Box as Well.
What He Said!
