Slight misfire no cel

[ogre20012001]

I need help.
2003 5.4 with intermittent miss at idle and a miss under load but it's not enough to set the check engine light.
It feels just like the last time I had a bad cop that was weak and not completely failed however that time it set the cel.
I need help to diagnose where my problem is.




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[JoeD]

I would recommend checking the plugs. I have eliminated the symptoms you describe by replacing the plugs and boots.

 

[ogre20012001]

I will check them thanks for the information


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[docraymund]

Do a cylinder balance test first.

 

[stamp11127]

When was the last tune up performed and how many miles are on the engine since then?

 

[1955moose]

What they said!


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[ogre20012001]

When was the last tune up performed and how many miles are on the engine since then?

About 6-9 months ago maybe little longer. No mor than 15,000 miles.
Did it my self changed all plugs and cop then about 3 month latter #7 cop took a crap on me and I changed just that coil and boot.


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[1955moose]

Have you had any coolant leaks above the coils? If your checking plugs, pull a few of the easy front ones. With only 15k on plugs, doubtful plugs are bad. It's a slight misfire, so that can be something as simple as insufficient fuel flow . When it shudders is it soft, or jerky? Soft is usually fuel related.


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[ogre20012001]

Have you had any coolant leaks above the coils? If your checking plugs, pull a few of the easy front ones. With only 15k on plugs, doubtful plugs are bad. It's a slight misfire, so that can be something as simple as insufficient fuel flow . When it shudders is it soft, or jerky? Soft is usually fuel related.


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Jerky
No coolant leaks


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[ogre20012001]

Last time I did tune up I thought it might be injectors so they are all new at last tune up along with fuel filter.
Forgot to mention that.
Also used motorcraft injectors.


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