I am running a 302 with a Holley Sniper EFI, I have about 2200 miles on the car now and I have long noticed that if the car sits for more than a day (two days definitely or God forbid three) the Engine tends to hesitate at acceleration, idle rough and then just clears up and runs like a bat out of hell. The system shouldn't be bleeding back...should it? Anyone else ever experienced this and if so what should I check for or investigate? As mentioned it runs awesome about 98%, but if it's been sitting you know it will be rough for what seems like a gallon, gallon and half of fuel.

Thanks