engine miss
02-13-2019, 06:22 AM
#3
Mark
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02-13-2019, 02:13 PM
#5
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Harry Kehm
Sorry about lack of info. Truck is an FX2 2007 5.4 ltr with 140, 000 miles. Original plugs replaced at 105,000 miles. When I thought it was bad gas I put dry gas and a can of Seafoam in the tank. It actually seem to improve for a few weeks. It happens when in OVERDRIVE and I accelerate.
02-13-2019, 03:22 PM
#6
Sounds like spark plugs/boots & springs
02-13-2019, 04:11 PM
#7
If the plugs were replaced 40k ago they are likely SP-515s, commonly go bad prematurely. They replaced them recently with the new SP-546 ones which are better. If you do plugs always do that boots as well.
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02-13-2019, 05:26 PM
#8
05 5.4l 3v s.crew lariat
You need new boots and plugs ,you have classic misfire symptoms
Do a hosp clean plug job . New spec for plugs is 60k from ford no more . Torque plugs in 25-28 foot pounds . Try to clean sparkplug tip area out with carb cleaner, that carbon around around tip causes problems Boots go bad with heat/oil/antifreeze/ age, one of the major causes of misfires .
Clean all cop contacts real good . You might want to change out injectors for new soon .
The threshold to set a cel for misfires is quite high . Misfires bad on cats ,don't push it .
Clean all cop contacts real good . You might want to change out injectors for new soon .
The threshold to set a cel for misfires is quite high . Misfires bad on cats ,don't push it .
02-14-2019, 06:35 AM
#9
Mark
iTrader: (1)
Sorry about lack of info. Truck is an FX2 2007 5.4 ltr with 140, 000 miles. Original plugs replaced at 105,000 miles. When I thought it was bad gas I put dry gas and a can of Seafoam in the tank. It actually seem to improve for a few weeks. It happens when in OVERDRIVE and I accelerate.
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SilverSport (02-14-2019)