HELP! Sputtering at low RPM 99 GT -

4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

Thread Tools Search this Thread
Old 07-03-2013, 10:15 PM   #1
Thread Starter
Join Date: Dec 2012
Location: AL
Posts: 2
Default HELP! Sputtering at low RPM 99 GT

My 1999 Mustang GT starts to sputter at low rpms when heated up but when I go above 2.1k RPM it runs perfectly fine and under WOT you can feel a small amount of hesitation and then it goes full power flawlessly. I have tried everything I could. I have replaced spark plugs, inspected COP, got a brand new MAF, cleaned throttle body and air filter, and had it professionally scanned for misfires or anything and nothing at all came up. I have no idea what it could be and it is extremely annoying . My question is, is this problem common and do any of you know for sure what it could be.
MercO5 is offline   Reply With Quote
Old 07-04-2013, 01:56 PM   #2
JJ Glo
1st Gear Member
JJ Glo's Avatar
Join Date: Mar 2013
Location: California
Posts: 91

Could be the IAC valve going bad and not being able to properly open and close to maintain a steady RPM.

My car started doing that before the IAC completely died. Perhaps the fact that I soaked it in TB cleaner helped speed up the process.

Or a vacuum leak.

Last edited by JJ Glo; 07-04-2013 at 02:29 PM.
JJ Glo is offline   Reply With Quote
Old 07-04-2013, 06:33 PM   #3
1st Gear Member
Doublevision's Avatar
Join Date: Mar 2013
Location: TN
Posts: 83

The fact it does it when warm suggests it could be electrically related to a sensor such as the IACV.
Doublevision is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Snow performance stage 2 MAF boos cooler install jwog666 Pipes, Boost & Juice 6 01-07-2018 08:16 AM
Engine tick Sixer4Life V6 (1994-2004) Mustangs 5 10-12-2015 05:26 AM
TNT, New PB TCStangerv6 Street/Strip 12 10-11-2015 06:57 PM
Low RPM hesitation / misfire between 900-1200 Omgitsa88Stang 5.0L General Discussion 5 10-05-2015 08:33 AM
Hi - Yes, I'm a gal and need help CS2007 General Tech 7 09-29-2015 08:38 PM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Featured Sponsors
Vendor Directory

All times are GMT -5. The time now is 12:12 AM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.