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

4.6 fluctuating idle

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Old Jan 13, 2004 | 07:05 PM
  #1  
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saleen338
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Default 4.6 fluctuating idle

<P class=Msonormal style="MARGIN: 0in 0in 0pt; mso-layout-grid-align: none"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">I have a 1999 Saleen s281 with the following aftermarket mods.BBK 70mm TB, C&amp;LMass air meter w/K&amp;N filter, C&amp;L true flow inlet pipe, C&amp;L true flow intake plenum, BBK X-pipe w/out cats<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o></SPAN></P>
<P class=Msonormal style="MARGIN: 0in 0in 0pt; mso-layout-grid-align: none"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'"><SPAN style="mso-spacerun: yes"></SPAN><o></o></SPAN></P>
<P class=Msonormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">Recently the idle has been fluctuating when at stop lights and it will also die occasionally, check engine light has also come on.<SPAN style="mso-spacerun: yes"> </SPAN>All indications are pointing towards a sensor or vacuum leak.<o></o></SPAN></P>
<P class=Msonormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'"><o></o></SPAN></P>
<P class=Msonormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Courier New'">Does anyone have an idea of which sensor it could be?</SPAN><o></o></P>
Old Jan 13, 2004 | 07:43 PM
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Default 4.6 fluctuating idle

what's the code????? that'll tell you the problem
Old Jan 13, 2004 | 07:56 PM
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saleen338
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Default 4.6 fluctuating idle

Havent run a diagnostic yet. Can you recommend a scanner?
Old Jan 13, 2004 | 08:05 PM
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Default 4.6 fluctuating idle

autozone will pull the code for free
Old Jan 13, 2004 | 08:06 PM
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Default 4.6 fluctuating idle



I use a Tech 2 on GManda Genesis on all others </P><edited><editID>Black Horse</editID><editDate>37999.7545601852</editDate></edited>
Old Jan 13, 2004 | 10:02 PM
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Default 4.6 fluctuating idle

autozone??
Old Jan 13, 2004 | 10:03 PM
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Default 4.6 fluctuating idle



do you not have an autozone?.... its a part store..like advance auto parts, etc...the one here will pull your codes for free</P>
Old Jan 13, 2004 | 10:17 PM
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Default 4.6 fluctuating idle



Thanks,</P>


Due to a statewide mandateAutoZone stores in Californiaare no long allowed to perform diagnostics test</P>
Old Jan 13, 2004 | 10:18 PM
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Default 4.6 fluctuating idle



Originally Posted by saleen338
Havent run a diagnostic yet. Can you recommend a scanner?
</P>


</P>


Yes, buy the scanner, they are handy..My opinion is that may be the IAC (Iddle air control) motor or valve may be dirty or bad --try cleaning it first..</P>


</P>


This the OBD code I got: </P>


</P>



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<T>
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<TD style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8; BACKGROUND-COLOR: transparent" vAlign=top>
<P class=Msonormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-FAMILY: 'Trebuchet MS'">P1507</SPAN><?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o></P></TD>
<TD style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8; BACKGROUND-COLOR: transparent">
<P class=Msonormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-FAMILY: 'Trebuchet MS'">Idle Air Control Underspeed Error
A vacuum leak, a damaged IAC assembly, a stuck IAC valve or throttle valve typically sets one or both of these codes. The IAC can be checked with a scan tool, sensor tester or multimeter. A vacuum leak is one of the most common causes and can be checked with a vacuum pump</SPAN><o></o></P></TD></TR></T></TABLE></P>


I have the same problem until I read this and fixed it myself.....</P>


Real case scenario:</P>
<P style="TEXT-ALIGN: center" align=center><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">IAC VALVE</SPAN></P>


<SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Question:</SPAN><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> 1996 Ford Mustang GT V8 mileage: 85,000. I'm at the end of my rope with Ford dealers and my Mustang. Several times every week the car will not start. I'll try to get it to start, but it acts like its not getting fuel. I'll give it fuel, and it will start, then it continually stalls until I get about five miles (this is a guess since the odometer doesn't work either) down the road. I have to give it a constant supply of fuel until it works out its kinks and runs correctly. Several dealers have taken a shot at it. I've been told everything from getting new plug wires (mine are fine) to the IAC Motor needs replaced. One dealer replaced a sensor on the engine, but it started acting up again shortly thereafter. Can you help? </SPAN></P>


<SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Answer:</SPAN><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"> Your problem is likely the idle air control motor (IAC). Replacing it should fix your stalling</SPAN></P>


<SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /><v:shape id=_x0000_t75 stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" oreferrelative="t" o:spt="75" coordsize="21600,21600"></v:shape></SPAN></P>


<SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><v:shape stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" oreferrelative="t" o:spt="75" coordsize="21600,21600"><IMG src=uploads/NO2JUNKIE/E2A29_iac.JPG border="0"></v:shape></SPAN></P>


<SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><v:shape stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" oreferrelative="t" o:spt="75" coordsize="21600,21600"></v:shape></SPAN></P>


<SPAN style="FONT-SIZE: 12pt; FONT-FAMILY: 'Times New Roman'; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><v:shape stroked="f" filled="f" path="m@4@5l@4@11@9@11@9@5xe" oreferrelative="t" o:spt="75" coordsize="21600,21600"> <v:stroke joinstyle="miter"></v:stroke><v:ulas><v:f eqn="if lineDrawn pixelLineWidth 0"></v:f><v:f eqn="sum @0 1 0"></v:f><v:f eqn="sum 0 0 @1"></v:f><v:f eqn="prod @2 1 2"></v:f><v:f eqn="prod @3 21600 pixelWidth"></v:f><v:f eqn="prod @3 21600 pixelHeight"></v:f><v:f eqn="sum @0 0 1"></v:f><v:f eqn="prod @6 1 2"></v:f><v:f eqn="prod @7 21600 pixelWidth"></v:f><v:f eqn="sum @8 21600 0"></v:f><v:f eqn="prod @7 21600 pixelHeight"></v:f><v:f eqn="sum @10 21600 0"></v:f></v:ulas><vath o:connect="rect" gradientshapeok="t" o:extrusionok="f"></vath><o:lock aspectratio="t" v:ext="edit"></o:lock></v:shape></SPAN><FONT face="Times New Roman" size=3>Idle air control valve</FONT></P>


</P>
Old Jan 13, 2004 | 10:19 PM
  #10  
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Black Horse
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Default 4.6 fluctuating idle

lol.... unless you have a buddy who has a scanner, looks like you've gotta fork out some money to the dealer..



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