It only lasts for a second, huh? What plugs are you running? I put in a off brand of spark plug and it was stutter if you quickly pushed the pedal down.
Our cars do have knock sensors so I would feel pretty safe in saying if it was detonation it would throw a code. Not to mention I don't see a motor making it a year with a lean condition.
What happens if you attempt to replicate this in park/neutral? If it's only under load it could possibly be a coil on its last leg.
And no problem buddy! That's what we're (most of us) are here for
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