2000 Chevy Camaro Car turns off when idling/slowing down

This problem just occured not long ago. I just had a tune up on the car about two weeks ago. I replaced my spark plugs (not the wires yet) and fuel filter. I also got an oil change and flush. My car is struggling accelerating and recently when I slow down either at a light or to make a turn my engine will shut off every time. When I can manage to get the car going it runs pretty rough but does fine. This often occurs more after I fill up my gas tank if that helps.