Welcome, I am Chris (aka-Moose)
When it occurs does it seem to happen when lugging the engine like going up a hill in 5th (OD)?
Does it feel like the engine has the hiccups?
So far I believe one of the coils is weak and not providing a strong enough spark and under certain speeds, rpms, loads, elevation, air fuel mix, and temp that weak spark is not able to fully ignite all the fuel.
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