• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Minor hanging RPMs

  • Thread starter Thread starter Jinx
  • Start date Start date Apr 13, 2012

Jinx

I like cats, cats like me. Cats and I fully agree.
20+ Year Stangneter
Oct 2, 2003
12,166
4,237
223
Cat Country
Apr 13, 2012
#1
  • Apr 13, 2012
  • #1
2003 GT
108k on the clock

RPMs seem to hang at initial start-up and when coming to a complete stop. They eventually drop to normal idle RPMs and there is no stumble or rough idle. I think it may be a sticking valve, because fuel consumption has not increased and power levels seem fine.

everything air related between the TB and exhaust manifold is original 2003 stock.

I've listened for vac leaks, and can't seem to hear any.

Any other suggestions before I take the IAC off for cleaning/replacement?? Is there a how-to write up somewhere??

TIA
 

N8Dogg98

15 Year Member
Apr 4, 2005
3,872
238
184
MN
Apr 13, 2012
#2
  • Apr 13, 2012
  • #2
Replace IAC = win

It's not rocket science... remove 2 bolts and the tubing running to the IAC and replace.
 

Jinx

I like cats, cats like me. Cats and I fully agree.
20+ Year Stangneter
Oct 2, 2003
12,166
4,237
223
Cat Country
Apr 13, 2012
#3
  • Apr 13, 2012
  • #3
Yeah, been a while since I've had to repair anything on the pony. Found out that most of my genuine Ford parts bookmarks are no longer valid. Need to find a new retailer that is trustworthy and economical.
 

N8Dogg98

15 Year Member
Apr 4, 2005
3,872
238
184
MN
Apr 13, 2012
#4
  • Apr 13, 2012
  • #4
Tousley Ford here in MN gives 10% over cost to forum members on SVTP and ModdedMustang... you could just call and ask for Kevin and tell him you're on one of the forums. He'll ship right to your door
 

Jinx

I like cats, cats like me. Cats and I fully agree.
20+ Year Stangneter
Oct 2, 2003
12,166
4,237
223
Cat Country
Apr 14, 2012
#5
  • Apr 14, 2012
  • #5
Got my first SES light today for this car since I bought it 9 years ago.
P 0171 Bank 1 lean
p 0174 Bank 2 lean

I removed the tubing from the IAC to the PCV valve and covered the port to the IAC with duct tape.
Then I started the car and the issue of the hanging RPMs has stopped.

Upon closer inspection (you will see why this is funny in a moment) it appears that I do indeed have a vacuum leak.















It's the 90* elbow from the tube that comes off the PCV valve just in front of the IAC valve body.
Now where can I get a replacement for it??
 

RedDaemon

10 Year Member
Mar 31, 2005
3,470
9
108
Atlanta, GA
Apr 14, 2012
#6
  • Apr 14, 2012
  • #6
i had a similar situation a few weeks ago. youll need to go to a parts store and buy a random vacuum hose they have in stock that has a right angle with the right diameter measurement. youll just have to cut it to fit
 

Jinx

I like cats, cats like me. Cats and I fully agree.
20+ Year Stangneter
Oct 2, 2003
12,166
4,237
223
Cat Country
Apr 15, 2012
#7
  • Apr 15, 2012
  • #7
Yeah, I have taken the rest of the tubing off so that I can use it at the store for fitment.
I saw that The stealership wants $40 on average for the tube assembly which consist of a 12" plastic tube and 2 of those 90* rubber ends.
 

Jinx

I like cats, cats like me. Cats and I fully agree.
20+ Year Stangneter
Oct 2, 2003
12,166
4,237
223
Cat Country
Apr 16, 2012
#8
  • Apr 16, 2012
  • #8
Well I found a high heat 90* coolant elbow for $5 at Discount Auto. It's not perfect, but it will work until I find a PCV elbow that is gas/oil resistant.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,131
21,298
234
Box behind Walmart
Apr 16, 2012
#9
  • Apr 16, 2012
  • #9
Jinx said:
Well I found a high heat 90* coolant elbow for $5 at Discount Auto. It's not perfect, but it will work until I find a PCV elbow that is gas/oil resistant.
Click to expand...


You should be able to find a preformed fuel line that is that size. Like mentioned before, you just have to cut it to fit. If you can't find it at the regular part stores, they should be able to order it. Diesel shops should have that stuff on hand.
 
Reactions: Jinx
You must log in or register to reply here.

Similar threads

O
Need a hand: Hanging idle with all new parts
  • Overused03
  • May 15, 2024
  • SN95 4.6L Mustang Tech
Replies
2
Views
1K
SN95 4.6L Mustang Tech May 21, 2024
Overused03
O
Dies at start up, mild surge
  • Dontknowchit
  • May 15, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
20
Views
868
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 9, 2025
Noobz347
F
Trouble Shooting Sudden Shift of AFR at low RPM
  • Farva_84
  • Jun 6, 2025
  • SN95 4.6L Mustang Tech
Replies
8
Views
500
SN95 4.6L Mustang Tech Jun 8, 2025
Farva_84
F
SURGING IDLE / NO IDLE CHECKLIST FOR 1996–1998 MUSTANG GT (4.6L 2V) - Work In Progress
  • Noobz347
  • Aug 30, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
748
1996 - 2004 SN95 Mustang -General/Talk- Aug 30, 2025
Noobz347
SURGING IDLE / NO IDLE CHECKLIST FOR 1999–2004 MUSTANG GT (4.6L 2V) - Work In Progress
  • Noobz347
  • Aug 30, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
923
1996 - 2004 SN95 Mustang -General/Talk- Aug 30, 2025
Noobz347
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?