Sergio, as mentioned above check the accerator pump curcuit. If that doesn't do it you may have it leaned out too much.
I can't remember offhand if the idle mix screws control air or fuel on an Edelbrock but I think air? Anyway if the mix screws are only out less than one turn from being seated so it runs ok it's generally a sign of too small of a main jet. If the acc pump is working then you may want to go to the next size larger jet.
If the mix screws control fuel and they need to be turned out 3+ turns to run good then it's the same deal, prolly too small a main jet.