5.0 Spark plug gap
#1
Did a little maintenance on my 2011 5.0 Screw today. Oil change, cleaned my air filter (K & N), checked tire pressures, etc. I've been noticing that my idle was a little rough and i would hear an occasional knock during light acceleration, so I checked my spark plugs. I pulled out a plug, and they looked ok for 30k miles, but the gap was off. The Ford manual states they should be set to .041 - .047. The plug was set to .055. I cleaned it, re-gapped it to .045, and reinstalled it, and checked the rest. All were from .055 - .057. The manual lists this as the recommended gap for the 3.7L motor, not the 5.0. Idle is smoother now, will see if my knock is gone tomorrow. Anyone find the same on their trucks?
#2
Senior Member
The mis-gap isn't surprising. Plugs are often (mistakenly) installed out-of-the-box without checking the gap 'cause they're gapped at the factory.
NOT!
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NOT!
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#7
Senior Member
Joewee3.5 ... That gap sounds super wide.
In general, forced induction plug gaps are less than those of naturally aspirated.
My EB gap is down to .28 and running great.
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keisur (12-25-2019)
#10
Senior Member
Well I finally found the time to check my plugs and they were all out of spec. One was right at .050 and all the other were .050+, but under .055. I set them all to .045. I noticed right away that the idle was smoother. Will have to see if it does anything for mileage.