Running rough at low speeds

[Jehr]

Hi everyone, I thought I would check with the collective wisdom before I bring my 2007 MTX into the shop. For the last couple weeks the engine has been repeatedly bogging down or missing at lower speeds, to the point of engine braking, then kicks back in. I would say 6000-8000 rpm. Happens hot or cold. Issue goes away at faster speeds. Seems to idle OK.

I changed the plugs, checked the air filter, ran some seafoam through. No improvement. Using premium gas all season.

Looking to see if I am missing any troubleshooting tips before I load it up. Appreciate any help and thanks.