2002 Mercedes Benz C320 car hesitates and idles rough

I recently moved to central florida where my car has had nothing but problems all of a sudden. 1st thing of note was parked in a parking lot for about 10 minutes with my ac on max, when I went to leave lot the car died. Restarted with all accessories still on, went to pull forward car died again. Took it to a mechanic who said my fuel pump was bad, fine, whatever. Get the car back, it runs worse than before with or without the ac running. Idles rough, hesitates when gas is applied and wanted to surge a couple of times when stopped at a light. Took it back to that mechanic and they cannot figure it out. Recent work performed after the 100k mark, new plugs, wires, valve cover gasket, oil change, sway bar bushings, fuel filter, and now fuel pump.