it idles/runs great for 5 minutes then won't idle

I ran out of gas then filled the gas tank up and have been driving for 3 months...Ran out of fuel, tried to start the engine. Filled up the tank and it would run well but not idle. Over time (3 months) after several fast accelerations and fuel additives, it now idles for first 5 minutes of drive then once I let off gas pedal, RPMs will bounce for a few seconds then die. Throughout this whole time, I've never had issues running it at higher RPMs and there is no check engine light on.