Car sputtering and idling rough after gas fill?

Flygirl0106

I just received a 2003 Mercedes c230 Kompressor 2 days ago with only 100,000 km on it. It had been sitting since the summer (4-6 months?) and had very little gas in it. It was driving perfectly and super smooth. I filled the tank last night with V-power gas from shell as well as took it through the touch less car wash and now, it’s running super rough, stalling, dragging when stepping on the gas and a knocking? Noise just started in the engine until I turned it off.
The check engine light came on this morning also. My best guess would be moisture in the tank from sitting so long, except that should have happened anyways before I filled it, wouldn’t it have?
Could it be a batch of bad gas?

PF_Flyer

After sitting for an extended period, it might simply be some moisture working its way out of the fuel lines