Looking for help, my 300 Touring started jerking under load a few months ago, happens when picking up speed or going up a hill. I think, but am not sure, that the issue is with the engine missing under load. No codes are shown so I can't be sure. I replaced the plugs today but no change at all. The problem could be with the transmission but I'm leaning towards engine.

Any help would be appreciated!

Thanks,
Duke