I recently purchased a 2001 F150 SC 4X4 witha 4.6. It has 39000 miles on it and I am having a problem with hesitation. When I first start it I usually let it warm for at least 30 seconds. It takes off fine from a standing start but if I am rolling slowly when I give it gas it does nothing for a few seconds then it finally will take off. When I say it does nothing, it doesnt really stall or stutter. It is if I didnt touch the gas at all. It seems to do this the first few minutes I drive it, then it seems fine. I have tried FI cleaner and premium fuel and it did nothing for it. I currently have done no mods but I plan to. Any help with this would be greatly appreciated. Thanks