• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Chasing a vacuum leak

  • Thread starter Thread starter Skoobie
  • Start date Start date Nov 28, 2004

Skoobie

Damn...Tyler65's hot!
May 25, 2003
655
0
17
Vancouver, WA
Nov 28, 2004
#1
  • Nov 28, 2004
  • #1
Well I got it all back together and took it for a spin and I still think theres a vacuum leak. I can hear a sucking sound in 4th at midrange rpms that get louder as I accelerate. Also the idle has trouble settling down and I seem to be sans some power. I just replaced a broken upper intake bolt and the upper intake gasket. Im pretty sure I got all the connections back on correctly. You cant hear any sort of leak at idle. So is there an easy way to test the system for a leak or do I need to start replacing all the hoses?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Nov 28, 2004
#2
  • Nov 28, 2004
  • #2
a vac gauge helps. stockish motor should pull 15-20" at idle (i pull 19.5). i think you are on the right track - a vac leak will make the idle hang (and slow the return from higher revs).

a vac leak can be heard upon heavy deceleration while in gear - manifold vac can go over 20".

some use the old WD-40 around vac lines trick - if the idle changes, there is a leak where you sprayed. be careful of possible fire hazzards while doing such testing (many products are flammable).

good luck.
 
You must log in or register to reply here.

Similar threads

E
Chasing Vacuum leak 99 GT
  • EBNS_2005
  • May 2, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
2
Views
110
1996 - 2004 SN95 Mustang -General/Talk- May 3, 2026
X-cam34
X
P
Engine Mysterious coolant leak at back of engine
  • palerider94
  • Jan 18, 2026
  • Fox 5.0 Mustang Tech
Replies
1
Views
164
Fox 5.0 Mustang Tech Jan 19, 2026
AeroCoupe
H
Engine 1987 5.0 HO vacuum hose locations
  • harryhaber
  • Jun 20, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
470
Fox 5.0 Mustang Tech Jun 21, 2025
limp
B
Engine Strange Noise
  • burntokita
  • May 8, 2026
  • Fox 5.0 Mustang Tech
Replies
8
Views
337
Fox 5.0 Mustang Tech May 11, 2026
keel
9
Unknown engine tick
  • 94 Daily
  • Oct 31, 2025
  • 1994 - 1995 Specific Tech
Replies
3
Views
143
1994 - 1995 Specific Tech Nov 1, 2025
91AOD5.0LX
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 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?