Strange Idle.

White5oh · 11-26-2002, 09:11 PM

I have been having a strange idle recently.

When I idle at a stop after about 20-30 seconds. The car idles extremely rough normally the car idles at 800 rpm when it starts to bog down it fluctuates from 800 to 500. Until i get going and from that point on the idle no longer seems smooth but rough idles from 800 to 750 and it gets worse after those 30 seconds of idling go by and begings to idle fluctuation. What can it be?

84LX89GT · 11-27-2002, 12:10 AM

Well, it could be the Idle air control valve sticking. Over time, carbon builds up in the idle air control valve and causes the valve to have poor/erratic operation and eventually it will stick in one position. I have pulled mine apart, replaced the rubber o-ring and cleaned out the inside with carb cleaner and it worked wonders. It's real easy to pull it apart and the cost of the gasket and o-ring is easily under $5 so it's worth a try even if it's not the cause because they tend to clog up anyway.
Keep us posted,

11-26-2002, 09:11 PM	#1
White5oh Registered Member Join Date: Dec 2001 Location: Kennewick, Wa Posts: 9	Strange Idle. I have been having a strange idle recently. When I idle at a stop after about 20-30 seconds. The car idles extremely rough normally the car idles at 800 rpm when it starts to bog down it fluctuates from 800 to 500. Until i get going and from that point on the idle no longer seems smooth but rough idles from 800 to 750 and it gets worse after those 30 seconds of idling go by and begings to idle fluctuation. What can it be? __________________ 1992 Mustang Gt BBK Equal Length Shorties, Phenolic Spacer, 65mm Throttle Body, Cold air Intake, BBK Underdrive Pullies and 183,000 Miles and Still BUCKIN!!

11-27-2002, 12:10 AM	#2
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	Well, it could be the Idle air control valve sticking. Over time, carbon builds up in the idle air control valve and causes the valve to have poor/erratic operation and eventually it will stick in one position. I have pulled mine apart, replaced the rubber o-ring and cleaned out the inside with carb cleaner and it worked wonders. It's real easy to pull it apart and the cost of the gasket and o-ring is easily under $5 so it's worth a try even if it's not the cause because they tend to clog up anyway. Keep us posted, __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

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