stumbling when going down the road
Forums at Modded Mustangs
Home Register FAQ Members List Calendar Timeslips Blogs Garage Gallery Auto Loans Search Today's Posts Mark Forums Read Auto Escrow


Go Back   Forums at Modded Mustangs > Mustang Forums > Modular Mustangs > 99 - 04

ModdedMustangs.com is the premier Ford Mustang Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools
Old June 24th, 2007, 01:59 AM   #1
Newbie
 
 
Join Date: May 2007
Posts: 14
kdb30 is on a distinguished road
iTrader: 0 reviews
Default

stumbling when going down the road


Guys I need some help.My 99 Mustang GT "stumbles" when cruising down the road.While idling it seems be a little rough,not too bad,just a little.Going through the gears it seems fine.However,when leveling off at highway cruising speed,it seems to jerk a tad.If I turn the defrost on it intensifies pretty good.Anybody know what could be wrong?Thanks in advance!
  Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old June 24th, 2007, 03:45 AM   #2
Hardcore Enthusiast
 
1999 Mustang
 
Join Date: Jul 2006
Posts: 1,354
Invictus is on a distinguished road
iTrader: 0 reviews
Send a message via AIM to Invictus
Default

clean you IAC, you can't do anything wrong by doing that. and also fluctuations at steady rpm is a symptom of your tps. check the voltage of it and see if it is to spec of not, it can be adjusted or replaced relatively cheap
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 02:07 PM   #3
Regular
 
 
Join Date: Apr 2007
Posts: 137
steve_stang2003 has a little shameless behaviour in the past
iTrader: 0 reviews
Default

Originally Posted by Invictus
clean you IAC, you can't do anything wrong by doing that. and also fluctuations at steady rpm is a symptom of your tps. check the voltage of it and see if it is to spec of not, it can be adjusted or replaced relatively cheap
+1

Also clean your MAF and check your air filter /box for contamination or the snorkel on loose etc.
Be VERY careful with the MAF and use only MAF cleaner or isopropyl alcohol.
Don't use carb cleaner as it is too caustic.
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 08:50 PM   #4
Regular
 
Baneful's Avatar
 
 
Join Date: Feb 2007
Location: Las Vegas
Posts: 117
Baneful is on a distinguished road
iTrader: 0 reviews
Send a message via Yahoo to Baneful
Default

I would like info on this too. My gt stumbles now on the highway at times, but doesn't seem to have any lack of power. I added a 1/2' copper pipe cap with a 1/4 hole drilled out to the iac line before the plastic black box to help the high idle drop. It helped the hanging idle, but it still stumbles at highway speeds while the ac is on. Could this just be the puter is still learning the airflow patterns? It seems every time my car wants to slow down while cc is on it stumbles.

I read it takes about 3 cycles of the ignition to learn the pattern, but I think I am past that.

I also read that the pipe cap worked on older gt's and that I need an iac restrictor plate instead of a cap... One side drilled to the iac hole size and the passanger side hole being smaller (depending on mods)...?
__________________
K&N fipk2 CAI, flowmaster 40 cat back, accufab 70mm tb/p, xcal2, 3.73 frpp gears, Steeda Tri-ax, Mach grill del.
255rwhp 295rwtq Needing more
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 08:55 PM   #5
Hardcore Enthusiast
 
Garhfer's Avatar
 
2004 Mustang GT Conv.
 
Join Date: Mar 2007
Location: Edgewater, FL
Posts: 1,800
Garhfer is on a distinguished road
iTrader: 0 reviews
Send a message via AIM to Garhfer
Default

Originally Posted by Baneful
I would like info on this too. My gt stumbles now on the highway at times, but doesn't seem to have any lack of power. I added a 1/2' copper pipe cap with a 1/4 hole drilled out to the iac line before the plastic black box to help the high idle drop. It helped the hanging idle, but it still stumbles at highway speeds while the ac is on. Could this just be the puter is still learning the airflow patterns? It seems every time my car wants to slow down while cc is on it stumbles.

I read it takes about 3 cycles of the ignition to learn the pattern, but I think I am past that.

I also read that the pipe cap worked on older gt's and that I need an iac restrictor plate instead of a cap... One side drilled to the iac hole size and the passanger side hole being smaller (depending on mods)...?
wtf? Who told ya adding that crap to your iac line would help?? I wouldn't start adding crap to my iac lines, Just clean out your iac and everything should be fine... why does a hanging idle bother people so much? it hangs for like a second so what...
__________________

2004 GT Boosted by Vortech
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 09:01 PM   #6
Hardcore Enthusiast
 
40thmustanggt's Avatar
 
 
Join Date: Jun 2007
Location: southcarolina
Posts: 1,381
40thmustanggt will become famous soon enough
iTrader: 0 reviews
Default

i agree its not a bad thing and it isnt going to hurt anything all 4.6 motors have it..
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 09:02 PM   #7
Hardcore Enthusiast
 
40thmustanggt's Avatar
 
 
Join Date: Jun 2007
Location: southcarolina
Posts: 1,381
40thmustanggt will become famous soon enough
iTrader: 0 reviews
Default

id try taking that crap off and seeing if it helps your stumble
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 09:39 PM   #8
MM's Mad Scientist
 
acmillr's Avatar
 
Slow Fella
 
Join Date: Jul 2006
Location: Ronceverte, WV
Posts: 5,101
acmillr is a splendid one to beholdacmillr is a splendid one to beholdacmillr is a splendid one to beholdacmillr is a splendid one to beholdacmillr is a splendid one to beholdacmillr is a splendid one to behold
iTrader: 2 reviews
Default

Does it stumble under heavy acceleration. If it doesn't, I would have to think it is a TPS problem.
__________________
  Reply With Quote Quick reply to this message
Old June 24th, 2007, 10:39 PM   #9
Newbie
 
 
Join Date: May 2007
Posts: 14
kdb30 is on a distinguished road
iTrader: 0 reviews
Default

Ok I have cleaned my IAC.It looked fine but I cleaned it anyway.The air filter and maf all is fine also.The car is fine under any acceleration.It runs like a champ under acceleration.Just at idle it seems rougher than it should.And of course at an even highway speed she stumbles.I guess I need to check the tps.Any pointers from you guys on checking the voltage?Thanks for all the previous advice guys.
  Reply With Quote Quick reply to this message
Old June 25th, 2007, 12:35 AM   #10
Regular
 
Baneful's Avatar
 
 
Join Date: Feb 2007
Location: Las Vegas
Posts: 117
Baneful is on a distinguished road
iTrader: 0 reviews
Send a message via Yahoo to Baneful
Default

Crap, didn't want to hijack. starting new thread.
__________________
K&N fipk2 CAI, flowmaster 40 cat back, accufab 70mm tb/p, xcal2, 3.73 frpp gears, Steeda Tri-ax, Mach grill del.
255rwhp 295rwtq Needing more
  Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Forums at Modded Mustangs forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools


Threads Similar to: stumbling when going down the road
Thread Thread Starter Forum Replies Last Post
Another stumbling mustang changed IAC and Tp Sensor onerealfastang 99 - 04 12 August 6th, 2009 06:02 AM
Road Course 07stanggt 2005 - 2010 11 June 13th, 2007 08:12 PM
86 stumbling under load hopper 5.0 Mustangs 6 April 25th, 2007 09:25 PM
Stumbling powerband issues continued. MySallyMI 99 - 04 2 March 14th, 2007 12:10 PM
stumbling in hawxter996 V6 Mustangs 20 March 6th, 2007 09:51 PM



All times are GMT -4. The time now is 06:17 PM.
Modded Mustangs is ©2005-2008, All Rights Reserved, And is Not Affiliated with Ford Motor Company.
Forum is powered by vBulletin ©2000 - 2014, Jelsoft Ent. Ltd. & SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.

powered by vBulletin ©2000 - 2014, Jelsoft Ent. Ltd.