Let me start by saying this is tried and tested, I have been running this plate since 2001. I have ran various combos over the years, big and small. Lets face it when you alter just about anything to the motor of a 5.0, you end up with the infamous hunting for an idle. In some cases the car will not idle at all. I will walk you through how to tune a non power added car. First off I am going to break down what the Idle air control or IAC does:
Frequently Asked Questions
Now that we have established what the IAC does and how it works, lets move onto what we can do to fix it.
You will need to buy this:
Ford Mustang IAC adjustable idle spacer kit 5.0 4.6
The IAC Spacer can be bought at most of your mustang shops.
Its very simple to install, simply disconnect your battery cable, and unplug your IAC which is located on the front of your throttle body. See pic
Google Images
Disconnect the connector this can be done with out any tools.
remove the two bolts holding the IAC onto the throttle body.
Remove the IAC and gasket.
Kit installation. Your kit will include two new gaskets, a spacer, 2 longer bolts and a allan head wrench. Remove it from the package. It will come with instructions, but they really dont help you, this is a trial and error.
It would be a good idea to go ahead and clean the IAC while it is apart. It is a two piece IAC and is held on with two phillips head screws. take it apart. It should be black from carbon build up. I clean mine with break parts cleaner, but I would suggest Throttle body cleaner, its not as harsh. I have never had any issues with cleaning my IAC with brake parts cleaner, so the choice is yours.
Next reassemble the IAC make sure its turned the right way. Its easy to get it backwards.
Installation of the spacer and IAC:
stick your new bolts through the IAC, then 1 gasket, next the spacer, and finally second gasket. It helps to keep it tilted back until you can get it up to the throttle body. Make sure the little bolts on the spacer are facing up not down. You will not be able to tune it if they are down. Reinstall the IAC and spacer, tighten the bolts down snug. Reinstall your plug and battery cables.
Tuning:
When you first start your car you will more then likely see no change in the idle or running. If you car will not stay started, you may need a friend to give it a little gas so that you can, keep the motor running. Depending on where you bolts in the spacer are at all the way out or all the way in, you will have to work it up or down. I turn each bolt 2 rounds at a time, until the car starts to idle on its own. you may need to adjust the idle set screw which is located under the throttle body. I just ran into this on my coupe yesterday. My car was almost all the way in, but after the EGR delete, and E85 switch the car was idling low 500 rpm. I backed the bolts on the spacer out, and messed with the set screw. To the right turns the idle up, to the left idles it down. After about 10 minutes I had the car idling perfect at 800 rpm.
I hope this helps yall with cams, and after market mods that make the computer hunt for an idle. If you have any questions let me know.
Frequently Asked Questions
Now that we have established what the IAC does and how it works, lets move onto what we can do to fix it.
You will need to buy this:
Ford Mustang IAC adjustable idle spacer kit 5.0 4.6
The IAC Spacer can be bought at most of your mustang shops.
Its very simple to install, simply disconnect your battery cable, and unplug your IAC which is located on the front of your throttle body. See pic
Google Images
Disconnect the connector this can be done with out any tools.
remove the two bolts holding the IAC onto the throttle body.
Remove the IAC and gasket.
Kit installation. Your kit will include two new gaskets, a spacer, 2 longer bolts and a allan head wrench. Remove it from the package. It will come with instructions, but they really dont help you, this is a trial and error.
It would be a good idea to go ahead and clean the IAC while it is apart. It is a two piece IAC and is held on with two phillips head screws. take it apart. It should be black from carbon build up. I clean mine with break parts cleaner, but I would suggest Throttle body cleaner, its not as harsh. I have never had any issues with cleaning my IAC with brake parts cleaner, so the choice is yours.
Next reassemble the IAC make sure its turned the right way. Its easy to get it backwards.
Installation of the spacer and IAC:
stick your new bolts through the IAC, then 1 gasket, next the spacer, and finally second gasket. It helps to keep it tilted back until you can get it up to the throttle body. Make sure the little bolts on the spacer are facing up not down. You will not be able to tune it if they are down. Reinstall the IAC and spacer, tighten the bolts down snug. Reinstall your plug and battery cables.
Tuning:
When you first start your car you will more then likely see no change in the idle or running. If you car will not stay started, you may need a friend to give it a little gas so that you can, keep the motor running. Depending on where you bolts in the spacer are at all the way out or all the way in, you will have to work it up or down. I turn each bolt 2 rounds at a time, until the car starts to idle on its own. you may need to adjust the idle set screw which is located under the throttle body. I just ran into this on my coupe yesterday. My car was almost all the way in, but after the EGR delete, and E85 switch the car was idling low 500 rpm. I backed the bolts on the spacer out, and messed with the set screw. To the right turns the idle up, to the left idles it down. After about 10 minutes I had the car idling perfect at 800 rpm.
I hope this helps yall with cams, and after market mods that make the computer hunt for an idle. If you have any questions let me know.
