Mechanics

NUMBER FOUR CYLINDER MISS FIRING.

2003 Ford F-150 • 5.4L V8 2WD Automatic • 130,000 miles

I changed out number four coil pack, changed all the spark plugs and cleared the code. It continued to miss fire and the light came back on, I took number three and number four coil packs and switched them out, cleared the code and still getting a miss fire on number four cylinder. I notice that number four fuel injector had a little corrosion. So I replaced the injector and the wire connectors still getting a miss fire. I am now thinking the plug and the coil pack may not be getting any fire. How do I check it and. What is your opinion, I am baffled.
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Mark robbins
February 4, 2014.




Misfires are very hard to diagnose even for a pro. About all you can do is check compression and if hta tis ok then have a pro doit as it can be a lot of things while driving your self completely nuts to fix it.

Hmac300
Feb 4, 2014.


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