engine sputters and dies

1998 FORD F-150
192,000 MILES
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STEVEPOONS
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My 98 Ford F150, 4.6L is sputtering and eventually dying in low idle. When the truck comes to a stop the RPMs drop below 500, the engine sputters and dies about 25% of the time. I've notice that when the engine sputters the lights also dim. What could the problem be?

I have been forced to put the truck in neutral at stops and lightly rev the engine to keep from stalling. Please help!
Nov 29, 2011 at 2:35 PM
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JACOBANDNICKOLAS
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Check for vacuum leaks and check idle air control valve.
Nov 29, 2011 at 7:31 PM
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STEVEPOONS
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Where is the idle air control valve?
Nov 29, 2011 at 8:28 PM
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JACOBANDNICKOLAS
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The IAC is located on the throttle body. It's purpose is to maintain idle speed based on input from the computer. On newer cars, the throttle plate is closed at idle; however, air still needs to get to the engine. Via the IAC, air is metered into the intake.
Nov 30, 2011 at 1:22 AM
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STEVEPOONS
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Replaced the IAC, and checked all vacuum lines. Still having the problem. What is the next possible issue?
Dec 1, 2011 at 6:55 PM
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JACOBANDNICKOLAS
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Those are the two items that can affect the idle. Have any trouble codes been retrieved?
Dec 2, 2011 at 5:04 AM
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