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

RPM range problem

  • Thread starter Thread starter ballajb64
  • Start date Start date Dec 7, 2009
B

ballajb64

New Member
Jul 13, 2006
76
0
0
California
Dec 7, 2009
#1
  • Dec 7, 2009
  • #1
I have a 1991 H.O motor with aluminum heads, longtube headers, F303 cam, typhoon upper and lower intake, and msd (dizzy,coil,6AL box) and 5speed transmission. For some reason i can not go past 3500 rpms, what could be the cause of this and what can I do to fix this problem?
 

2000xp8

SN Certified Technician
Aug 8, 2003
8,033
1,625
194
NJ
Dec 7, 2009
#2
  • Dec 7, 2009
  • #2
Make sure there isn't a 3500 rpm pill installed in the msd box.
Make sure the throttle cable isn't hung up on anything.
Bypass the msd box, see if that fixes the problem.
 
B

ballajb64

New Member
Jul 13, 2006
76
0
0
California
Dec 7, 2009
#3
  • Dec 7, 2009
  • #3
ok ill try that
 
B

ballajb64

New Member
Jul 13, 2006
76
0
0
California
Feb 10, 2010
#4
  • Feb 10, 2010
  • #4
k so now i replaced my fuel regulator with a holley adjustable one. The problem is still happening. Now i am starting to wonder if it could be my msd box. I have a MSD 6AL which has a rev limiter... So im wondering if i need to take that to get tested.
 

2000xp8

SN Certified Technician
Aug 8, 2003
8,033
1,625
194
NJ
Feb 10, 2010
#5
  • Feb 10, 2010
  • #5
Just bypass the msd box, should only take a minute if you used the adapter harness.
 
B

ballajb64

New Member
Jul 13, 2006
76
0
0
California
Feb 10, 2010
#6
  • Feb 10, 2010
  • #6
i did not use the adaptor harness... so what would i have to do to bypass it?
 
You must log in or register to reply here.

Similar threads

8
Foxbody high rpms and surging rpms
  • 86foxseth
  • Jun 9, 2026
  • Fox 5.0 Mustang Tech
Replies
4
Views
217
Fox 5.0 Mustang Tech Jun 13, 2026
Noobz347
J
Engine Running like crap :(
  • justadude07
  • Sep 27, 2025
  • Fox 5.0 Mustang Tech
Replies
8
Views
357
Fox 5.0 Mustang Tech Oct 19, 2025
DadLife0724
R
1974 Datsun 620 pickup / 5.0L HO
  • RJH46
  • Aug 24, 2025
  • Other Auto Tech
Replies
1
Views
248
Other Auto Tech Aug 24, 2025
Noobz347
Drivetrain 83’ Glx convertible C5 Trans help!
  • JacksonJared2113
  • Dec 25, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
401
Fox 5.0 Mustang Tech Dec 26, 2025
JacksonJared2113
R
94’ SN95 - Intermittent lope & bogging at moderate rpm
  • Red5.0ho
  • Nov 2, 2025
  • 1994 - 1995 Specific Tech
Replies
5
Views
474
1994 - 1995 Specific Tech Nov 3, 2025
General karthief
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?