STILL rough idle
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STILL rough idle
hi im a little confused i wen out this morning at 630,woke up togo to work but they didnt need me im 16. so i decided to take to the idle problom the 5.4 has
im pretty sure i found the boot that everyone is talking about that looks like a spark plug wire boot thoing but it seemed fine adn tough. and it still does it when you come to a stop. it idles fine for about 3 sec. then it dips down like 75-100 rpm and shakes the truck a little bit tried turning off a/c still does it dont know what to do help me out
im pretty sure i found the boot that everyone is talking about that looks like a spark plug wire boot thoing but it seemed fine adn tough. and it still does it when you come to a stop. it idles fine for about 3 sec. then it dips down like 75-100 rpm and shakes the truck a little bit tried turning off a/c still does it dont know what to do help me out
Elder User
Joined: Jun 2004
Posts: 679
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From: Orlando, Fla
Can you be more specific, Year, motor size and mileage? What I believe you are describing is a COP (Coil Pack)? There are 8 of them, they are on the top of the 5.4, the 4.6 depends on what year you have for the ignition system type.
Specifically on the 5.4, these are located under the fuel rails along the top of the cylinder heads where they meet the intake manifold. The 4.6 ltr. plugs I believe are located at the exhaust manifolds.
If you have a failed COP, you should be getting a blinking check engine light. If so, you can either go to Ford to have them pull the code (about $85) or you can purchase a code checker from your local parts store for about $150. The nice thing about Ford's code system is it will tell you which COP has failed so you don't have to play around. The bad thing about going to Ford is, that's only the diagnostic cost, they will try to charge you another approx. $340 for the work ($99 for the COP, $8 plug, and the rest in labor). If you get the code checker, you don't have to rely on anyone and it pays for itself in 2 checks. Pick up a Haynes manual (about $15), it lists the codes an cause and can handle most of your typical needs.
I also suggest you check the DPFE located on the drivers side of the throttle body. Its about playing card size and about 5/16" thick with 2 vacuum lines to it. If its original, it will corrode from being made of potmetal, the replacement is plastic. Check the vacuum lines to it also, they dry up and split at the ends. Replacement is regular fuel line, make sure to take both lines to the store, they are different sizes.
Specifically on the 5.4, these are located under the fuel rails along the top of the cylinder heads where they meet the intake manifold. The 4.6 ltr. plugs I believe are located at the exhaust manifolds.
If you have a failed COP, you should be getting a blinking check engine light. If so, you can either go to Ford to have them pull the code (about $85) or you can purchase a code checker from your local parts store for about $150. The nice thing about Ford's code system is it will tell you which COP has failed so you don't have to play around. The bad thing about going to Ford is, that's only the diagnostic cost, they will try to charge you another approx. $340 for the work ($99 for the COP, $8 plug, and the rest in labor). If you get the code checker, you don't have to rely on anyone and it pays for itself in 2 checks. Pick up a Haynes manual (about $15), it lists the codes an cause and can handle most of your typical needs.
I also suggest you check the DPFE located on the drivers side of the throttle body. Its about playing card size and about 5/16" thick with 2 vacuum lines to it. If its original, it will corrode from being made of potmetal, the replacement is plastic. Check the vacuum lines to it also, they dry up and split at the ends. Replacement is regular fuel line, make sure to take both lines to the store, they are different sizes.
Last edited by High_Horse; Aug 1, 2005 at 12:06 PM.
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