A little technicle know how needed. When I HAMMER on my gas, mainly from a stop, it hesitates if not dies out. If it does not die out it hesitates and then chuggs to get going. If I have some speed up and hammer down, the 4 barrel dumps and I go. I just had a mechanic rebuild my carb with a kit. I thought it was a bad accelerator pump but still doing it. He did say it did not come with the new pump but it did have a new rubber seal for it. Any Idears? Thanks for the Help.