Chasing a rough idle on a 2014 V6 Mustang
#1
Chasing a rough idle on a 2014 V6 Mustang
Hello all,
My 2014 V6 manual has started to idle a bit rough. It has 160k miles and it started getting rough about 20k miles ago. I have tried several different things to see if anything would help solve it. Such as...
- New NGK plugs and boots (155k)
- New injectors (155k)
- Checked harmonic balancer, looks good, no wobble and rubber seal is still spongy (155k)
- Checked motor mounts - engine lifts less than 1 inch in either direction (155k)
- Cleaned MAF sensor (150k)
- Replaced throttle body (got stuck closed at 150k)
- New belt tensioner + serpentine belt (150k)
- Checked alternator, A/C, water pump pulleys - no play or noises
- Fresh oil every 5k, cleaned K&N air filter every change
- Checked all hoses connecting to air intake pipe, no cracks and all connected
Car actually performs better on the road. But the shaking at idle is still here. No cutting out at high rpm, no power loss. Just idling rough. You can see the rpm dipping and returning to around ~600rpm constantly, and the shaking is amplified 2x by having the A/C on because it seems like it fluctuates harder to stay at 600rpm.
When I actually peek my head into the engine bay while it is running, I can hear a faint, low pitch whistle noise. It almost seems like a vacuum leak. If I had to guess where it is coming from, it is either on the front-drivers side of the engine or up near the ABS module. Any revving gets rid of the whistle. I am at my wits end with this issue and would love to hear any insight you guys may have. Let me know if any more info is needed!
My 2014 V6 manual has started to idle a bit rough. It has 160k miles and it started getting rough about 20k miles ago. I have tried several different things to see if anything would help solve it. Such as...
- New NGK plugs and boots (155k)
- New injectors (155k)
- Checked harmonic balancer, looks good, no wobble and rubber seal is still spongy (155k)
- Checked motor mounts - engine lifts less than 1 inch in either direction (155k)
- Cleaned MAF sensor (150k)
- Replaced throttle body (got stuck closed at 150k)
- New belt tensioner + serpentine belt (150k)
- Checked alternator, A/C, water pump pulleys - no play or noises
- Fresh oil every 5k, cleaned K&N air filter every change
- Checked all hoses connecting to air intake pipe, no cracks and all connected
Car actually performs better on the road. But the shaking at idle is still here. No cutting out at high rpm, no power loss. Just idling rough. You can see the rpm dipping and returning to around ~600rpm constantly, and the shaking is amplified 2x by having the A/C on because it seems like it fluctuates harder to stay at 600rpm.
When I actually peek my head into the engine bay while it is running, I can hear a faint, low pitch whistle noise. It almost seems like a vacuum leak. If I had to guess where it is coming from, it is either on the front-drivers side of the engine or up near the ABS module. Any revving gets rid of the whistle. I am at my wits end with this issue and would love to hear any insight you guys may have. Let me know if any more info is needed!
Last edited by quipple; 8/12/23 at 01:00 PM.
#2
Administrator, Shop Manual PDF Poster, Parts Locator & Spam Bot Eliminator!!
Join Date: November 27, 2004
Location: Visalia Ca.
Posts: 10,231
Received 2,606 Likes
on
1,930 Posts
Have You Checked For Any DTC Codes???
Here is What the Shop Manual Says About Vacuum Leaks!
KC
Also Give a Look Here! Not Exactly Your Scenario But A Good Reference For Checking Vacuum Leak! I would Give a Hard Look at Actual Intake Manifold For Leaks!
https://themustangsource.com/forums/...7/#post7069162
,
,
,
Here is What the Shop Manual Says About Vacuum Leaks!
- Listen for vacuum leaks.
- Inspect the entire intake air system from the mass airflow (MAF) sensor to the intake manifold for leaks such as:
- cracked or punctured intake air tube.
- loose connections on the intake air tube at the air cleaner housing or throttle body
- EGR valve gasket leak to intake manifold
- intake manifold assembly or gasket
- EGR valve diaphragm or control solenoid
- vacuum supply connectors and hose
KC
Also Give a Look Here! Not Exactly Your Scenario But A Good Reference For Checking Vacuum Leak! I would Give a Hard Look at Actual Intake Manifold For Leaks!
https://themustangsource.com/forums/...7/#post7069162
,
,
,
Last edited by 05stangkc; 8/12/23 at 01:32 PM.
The following users liked this post:
quipple (8/12/23)
#3
Checked, no stored codes. I'm going to recheck my entire air intake assembly and EGR valve. I had the EGR replaced about 20k miles ago as well, EVAP code popped up on me in the past. Thank you for the advice.
#4
Administrator, Shop Manual PDF Poster, Parts Locator & Spam Bot Eliminator!!
Join Date: November 27, 2004
Location: Visalia Ca.
Posts: 10,231
Received 2,606 Likes
on
1,930 Posts
This Is The Best $30.00 I Ever Spent For a Tool!
FUEL TRIM
https://www.thedrive.com/cars-101/38...m-fuel-trim-be
Mgb,
KC
#5
I took measurements of the fuel trim today. It seems to be adding 10-15% at idle short term, long term reads -(0-3)% depending on the bank. The short term fuel trim has me worried, as it seemed to fluctuate with the vibration but I cannot confirm that.
Short term trim, Bank 1 at idle
Short term bank 2, long term bank 1/2 at idle
Short term trim, Bank 1 at idle
Short term bank 2, long term bank 1/2 at idle
#6
I'm going to try and spray MAF cleaner around all my hose connections and intake plenum/manifold to see if I can get the idle to change. If not, I'll smoke into the intake and try that way.
#7
#8
Yup. Ran a tank of seafoam concentrate and really sprayed out the MAF sensor in the intake. Idle is much smoother now! Just hit 165k miles, I'd do a full induction cleaning on the intake side at a shop. That was also something early on that helped out with all the carbon buildup in the lower manifold.
Last edited by quipple; 4/29/24 at 07:14 PM.
#9
THE RED FLASH ------ Master-Moderator
Thanks for following up and pleased that a full induction cleaning took care of the rough idle concerns.
#10
Legacy TMS Member
Join Date: January 25, 2010
Location: Massachusetts
Posts: 3,777
Received 1,509 Likes
on
1,031 Posts
what is a "full induction cleaning" -- it is that like when you spray (or suck) Sea Foam into the intake manifold?
I have read good and bad opinions about that over the years and was just wondering what is the latest consensus .... it seems like a good thing to clean the gunk and carbon out, but a bad thing to spray nasty chemicals into the engine that don't belong there
I have read good and bad opinions about that over the years and was just wondering what is the latest consensus .... it seems like a good thing to clean the gunk and carbon out, but a bad thing to spray nasty chemicals into the engine that don't belong there
#11
Administrator, Shop Manual PDF Poster, Parts Locator & Spam Bot Eliminator!!
Join Date: November 27, 2004
Location: Visalia Ca.
Posts: 10,231
Received 2,606 Likes
on
1,930 Posts
what is a "full induction cleaning" -- it is that like when you spray (or suck) Sea Foam into the intake manifold?
I have read good and bad opinions about that over the years and was just wondering what is the latest consensus .... it seems like a good thing to clean the gunk and carbon out, but a bad thing to spray nasty chemicals into the engine that don't belong there
I have read good and bad opinions about that over the years and was just wondering what is the latest consensus .... it seems like a good thing to clean the gunk and carbon out, but a bad thing to spray nasty chemicals into the engine that don't belong there
https://www.bgprod.com/platref/
KC
Thread
Thread Starter
Forum
Replies
Last Post