Hesitation when hitting the gas

[rico750sxi]

I noticed this today when I pulled my truck out of the garage to let it run for a while. Right before I was pulling it back in I decided to give a couple of blips on the throttle. Each time I hit the gas there was a sucking type sound, followed by a delay and then the engine would rev. Anybody experience this? I searched and didn't see any previous posts. I don't remember if it was there before the Predator and Volant were installed. I should also mention that this tank of gas has been in the truck since November 9th!! I also want to take it for a ride to see if it does it when in gear. Then I will reload the stock computer program and see. Any suggestions on some other things?

Thanks