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Morning, I have a 1992 Mustang GT 5.0 and decided to changed out my valve cover gaskets. During this process I installed new hoses on the intake, due to cracks. Now that I've put everything back together, the car will crank, but will not stay running. It'll fire up fine, but will not idle. I've read post of unplugging the IAC and trying to crank it, too also try disconnecting the battery, so that the IAC can reset and last but not least, that the EGR valve could be stuck open and causing the issue.

Has anyone had this issue?
 

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First off I'd find a vacuum diagram on google to make sure all of your vacuum lines are connected properly, especially the ones under the intake and especially the PCV valve to upper intake hoses. If you have major vacuum leaks the engine won't stay on.
 
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It sounds like you might have a vacuum leak. When the engine is idling, it's supposed to be running at a steady RPM. If there's a vacuum leak, it will cause the engine to speed up and slow down as the air leaks in and out.

One way to test for a vacuum leak is to spray some soapy water around the intake manifold and see if any bubbles form. If there are any bubbles, that means there's a leak somewhere and you'll need to track it down and fix it.

Another thing you can do is check the idle mixture screws to make sure they're set correctly.
 

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It sounds like you might have a vacuum leak. When the engine is idling, it's supposed to be running at a steady RPM. If there's a vacuum leak, it will cause the engine to speed up and slow down as the air leaks in and out.

One way to test for a vacuum leak is to spray some soapy water around the intake manifold and see if any bubbles form. If there are any bubbles, that means there's a leak somewhere and you'll need to track it down and fix it.

Another thing you can do is check the idle mixture screws to make sure they're set correctly.
Please explain more about checking the idle mixture screws. Where are they located on a 92 GT? How to you adjust them? How many are there?
 

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It sounds like you might have a vacuum leak. When the engine is idling, it's supposed to be running at a steady RPM. If there's a vacuum leak, it will cause the engine to speed up and slow down as the air leaks in and out.

One way to test for a vacuum leak is to spray some soapy water around the intake manifold and see if any bubbles form. If there are any bubbles, that means there's a leak somewhere and you'll need to track it down and fix it.

Another thing you can do is check the idle mixture screws to make sure they're set correctly.
Please provide a picture showing where the idle mixture screws are on an injected 5.0.
 
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