Car starts but won't stay running acts like it's out if gas

Hello, If the car will not stay running, or runs rough at idle, how does it operate if you press the gas? If everything smooths out once it is above idle, check your idle air control valve (IACV), which allows air into the engine when the throttle is closed. How does it run right now? Does it stay running, or shut off? I can't tell from your description. Also, let me know what engine speed it is idling at. Why were the other parts replaced? Servicehttp://repairpal.com/volvo-within-10-miles-of-warrensburg-missouri-64093 history?