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496 mag fluctuating Rpm , while going fast

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Old 08-19-2022 | 05:34 PM
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Default 496 mag fluctuating Rpm , while going fast

Both motors run all day 3000-3400 rpm, if i hit the gas slowly bring it up around 4k. Port motor fluctuates rpm down and up rapidly like its bogging. But runs fine at slower speeds.
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Old 08-19-2022 | 05:43 PM
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Fuel filter replaced?
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Old 08-20-2022 | 07:25 AM
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What's your serial number?
Might be a fuel restriction filter as Rookie mentioned, the anitsiphon valve, or weak fuel pump or boost pump (if there is one)

Put a pressure gauge on the fuel rail
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Old 08-20-2022 | 01:01 PM
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Start with the basics. Change the spark plugs and fuel filter.
A friend had similar issues and replaced plugs and wires and all was good.
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Old 08-20-2022 | 05:32 PM
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plugs and wires brand new and water separator filter, i will check fuel pressure at rail and while its running. thanks bob
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Old 08-23-2022 | 06:58 AM
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I can't promise this is your issue, but Crankshaft Position Sensors on the 496s can present RPM fluctuation issues and not throw an error code.
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