MustangWorks.com - The Ford Mustang Power Source!

Go Back   MustangWorks.com : Ford Forums > Mustang & Ford Tech > Windsor Power
Register FAQ Members List Calendar Mark Forums Read

Reply
 
LinkBack Thread Tools Rate Thread Display Modes
Old 12-30-2006, 10:45 AM   #1 (permalink)
Jeff Stockham
Registered Member
 
Join Date: Dec 2006
Posts: 2
Default 5.0 mustang low RPM miss

I have a 1990 5.0 Mustang that has developed a high-load, low-RPM miss. The miss is most noticable at WOT below 2000 RPM and goes away with increasing RPM. My guess is that it is ignition related. I have replaced the plugs, wires, distributor cap, rotor, coil, and the TFI module with no success. It has slowly gotten worse over time.

Any suggestions would be appreciated.

Thanks,

Jeff
Jeff Stockham is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 12-30-2006, 02:32 PM   #2 (permalink)
Mr 5 0
Conservative Individualist
 
Mr 5 0's Avatar
 
Join Date: May 1997
Location: Wherever I need to be
Posts: 7,487
Exclamation Re: 5.0 mustang low RPM miss

This is a tech question and should be moved to the Windsor Power forum.
__________________
5.0 Mustang Owner
1990 - 2005
Mr 5 0 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 12-30-2006, 06:29 PM   #3 (permalink)
Capri306
Moderator
 
Capri306's Avatar
 
Join Date: Sep 1998
Location: Grand Rapids, Michigan, USA
Posts: 1,001
Default Re: 5.0 mustang low RPM miss

No problemo.

Mebbe you're leaning out. Is it just when the engine is at operating temperature, or all the time? Have you tested the MAF sensor?
__________________
Capri306, Moderator
The Mustang Works Online

1979 Mercury Capri
1987 5.0L Mustang LX Notchback
1993 5.8L Eddie Bauer Bronco
Capri306 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 12-31-2006, 10:48 PM   #4 (permalink)
Jeff Stockham
Registered Member
 
Join Date: Dec 2006
Posts: 2
Default Re: 5.0 mustang low RPM miss

The miss appears to be independent of engine temperature. The mass airflow sensor was replaced a couple of years ago. It's the most noticable in 5th gear.
Jeff Stockham is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 01-08-2007, 12:54 PM   #5 (permalink)
USMC302
Registered Member
 
USMC302's Avatar
 
Join Date: Apr 2001
Location: Gallatin, Tn
Posts: 1,326
Default Re: 5.0 mustang low RPM miss

Sounds like timing. What's it set at right now?
__________________
USMC302 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 01-08-2007, 10:17 PM   #6 (permalink)
Coupe50h
Registered Member
 
Coupe50h's Avatar
 
Join Date: Aug 2002
Location: SanAntonio, Tx
Posts: 957
Default Re: 5.0 mustang low RPM miss

Any mods?
If you have aftermarket rockers, adjustment could be out, you could be losing compression? just a guess.

Also, sounds ignition related, but it could be a weak fuel pump, you need to be sure your getting fuel pressure.
And that you dont have a defected coil, even if it's new.
Check engine grounds, and see if you can run a code scanner, and pull codes. could be a number of things, clean the maf, i dont care if it's new, and make sure all injectors are squirting.
good luck..
__________________
X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's.
race weight 3,160

12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear

13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear
Coupe50h is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 01-09-2007, 07:07 PM   #7 (permalink)
Unit 5302
Registered Member
 
Join Date: May 1999
Posts: 5,245
Default Re: 5.0 mustang low RPM miss

Is it an audible misfire (backfire?) Does it clear itself out after a few pops?

Either one of those scenarios sound you could have a broken or failing fuel injector.
Unit 5302 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Sponsored Links
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



Similar Threads
Thread Thread Starter Forum Replies Last Post
Safety Issue 64 - 70 Mustangs Mach1 Cobra Jet Classic Mustangs 20 07-11-2005 09:06 PM
Edelbroock RPM head on a 393 Redge Windsor Power 3 06-22-2005 11:55 PM
I NEED HELP! OK a REAL 1976 Mustang II suspension on a 65 Mustang coup! Raymond56 Classic Mustangs 1 06-15-2005 07:01 PM
t-5, is it the same in the 4 cylinder and V8 ex-lt1-guy Windsor Power 12 03-03-2002 01:59 AM
89-Mustang pulling trailer -vs- 2000 Mustang Five0 Stang Stories 7 04-01-2001 03:50 AM


All times are GMT -5. The time now is 03:17 AM.


SEARCH