This started a couple of days ago. When i park my truck for a while like 4 or more hours when i got back out to restart it it won't start. It will just sit there cranking. If I start feathering the gas pedal it will get some life and start to try and fire. After about 2 minutes of doing that, It will finally start up but starts at really really low RPM and I have to keep it floored til the RPM's come up. Once the truck is running it runs fine. And I can park it run into a store and come back out and it will start up just fine. But mainly wont start after it sits out all night or while it sits while I'm at work. Any help would be greatly appreciated. Thank you so much.