At 40 - 50 mph. My f-150 Larrit. 4.6. Starts to jerk .........sputter. The rpms stay the same. So I'm leaning towards spark plugs or coil pack any chance of trams problems ?
Sounds like a good tune up along with a air filter.
This is a common issue with the Ford 4.6L . The problem is most likely the spark plugs and COP coils. I purchased the Accel COP coils from Summit Racing. I bought an 8 pack of the Accel coils from Summit for $170.00 and they work great! Most other vendors wanted around $400.00 for the same thing. When installing, be sure to use anti-seize on the spark plug threads, and a dab of dielectric grease inside the spark plug boots.
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