hello im new to this site,i have a 99 silverado with a 5.3 vortec, and i am not very mechanically inclined my dad usually helps me. But n.e how when i start to accelerate to take off, my trucks feels like it slips for 3-4 secomds then runs fine through all gears, in reverse i hit the gas and smoke the tires, it only happens in first gear, i had the tranny rebuilt bout 1.5 years ago, so its under warranty, i took it to the tranny guy he said he checked it and was fine but i think he hooked up pressure test and wat ever else im sure he didnt take my tranny apart, so is there anything that can not be showing up on the diagnostic, tranny guy says its a fuel problem, im totally lost any help is appreciated,,, cpl other people said too look into fuel filter, dirty fuel injectors, torque converters, thnx in advance