1999 Chevy Cavalier Hard starting

1999 Chevy Cavalier, When the car sits for a few days unattended I can go out to it turn the key and it fires right up. I can drive it around town, up steep hills, or just straight away and it runs fine. If I shut it off I can restart it immediately no problems but when it sits for about 5 - 10 mins it will not restart without me giving it some gas... Or just keep the engine cranking for about 10 - 20 seconds without giving it gas it sometimes starts up. I have replaced the ignition coil because there was a slight miss also replaced the plugs and the Idle Air control motor because it had a carbon build up on it. Checked the fuel injectors and they are not leaking and it looked like a good spray when tested.