if you can verify it isnt a misfire, Id say its your rotating mass. i had a similar problem and it was a defective pressure plate.yes I know yours is auto but I m just saying it sounds similar. Mine was so bad the dash rattles sitting still
See that is the thing. Nothing in the car rattles. Its not that kind of vibration, I can feel it in my seat. It was interesting because I thought for sure it was pinion angle/driveline related so I took it my driveline guy and we drove it and he immediately went to engine vibration. He is the one who had me rev it in N to confirm.
He shares the lot with a racecar builder and he came over and watched the engine with the hood open, while I revved and he asked "whats vibrating?" I said sit in the passenger seat and you can feel it in your bottom.
