Truck misfiring
01-19-2018, 08:42 PM
#1
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Truck misfiring
I have a 2008 5.4 F-150 that started running rough last summer. At the time I was told to change plugs and coils which I did. About a week ago it started again so I took it to an auto parts store and had them plug into it. It had several faults all related to the coils. Is it possible the coils went bad that quickly? They are Access coils. Could it be plugs? Can't remember which plugs I installed.
01-20-2018, 08:35 AM
#2
Mark
iTrader: (1)
What are the DTC’s ?
01-20-2018, 09:08 AM
#3
Moderator
I second this^^^
Most misfires can be resolved with new plugs (Motorcraft), new boots and springs on the coils, new coils and finally but rarely the injectors. This will not fix them all but is usually the best solutions. I replaced all the boots and springs on my coils about 6 months ago. I have since had to pull the coils back off, clean out some slight debris (dirt and moisture) on two of the boots. I simply removed the coil, took off the boot and spring, ran a paper towel through the boot (from top to bottom so I don't track more dirt and dielectric grease further into the boot), then cleaned the spring very well with some electrical contact cleaner, cleaned the connection between the spring and the coil with electrical contact cleaner, put it all back together, put on new dielectric grease (very small amount careful not to get any on the spring) and reinstalled everything. Both misfires went away immediately. These trucks are pretty sensitive when it comes to their plugs, boots and springs, and coils. I don't know anything about Accel brand coils, seems like people have said to shy away from them but there are a few aftermarket coils that have been working for many members on here.
Most misfires can be resolved with new plugs (Motorcraft), new boots and springs on the coils, new coils and finally but rarely the injectors. This will not fix them all but is usually the best solutions. I replaced all the boots and springs on my coils about 6 months ago. I have since had to pull the coils back off, clean out some slight debris (dirt and moisture) on two of the boots. I simply removed the coil, took off the boot and spring, ran a paper towel through the boot (from top to bottom so I don't track more dirt and dielectric grease further into the boot), then cleaned the spring very well with some electrical contact cleaner, cleaned the connection between the spring and the coil with electrical contact cleaner, put it all back together, put on new dielectric grease (very small amount careful not to get any on the spring) and reinstalled everything. Both misfires went away immediately. These trucks are pretty sensitive when it comes to their plugs, boots and springs, and coils. I don't know anything about Accel brand coils, seems like people have said to shy away from them but there are a few aftermarket coils that have been working for many members on here.
01-20-2018, 09:11 AM
#4
Moderator
Also, all this took me a grand total of 20 minutes to clean up the boots and springs on two cylinders.
01-22-2018, 08:41 AM
#5
Yes its possible.
Use only correct motorcraft plugs and coils, unless you know for SURE an aftermarket coil is good. Most are cheap chinese junk. You might trust denso . Cheap ones break down at that the spark gap/voltage the 5.4 uses. A wide gap or lean cyl issue will also lead to early demise by increasing the spark voltage on coils secondary.
Use only correct motorcraft plugs and coils, unless you know for SURE an aftermarket coil is good. Most are cheap chinese junk. You might trust denso . Cheap ones break down at that the spark gap/voltage the 5.4 uses. A wide gap or lean cyl issue will also lead to early demise by increasing the spark voltage on coils secondary.
Last edited by mbb; 01-22-2018 at 08:43 AM.
01-22-2018, 11:01 AM
#6
Mark
iTrader: (1)
He must of been a 1 post wonder
