so, when you are at a standstill, and you need to accelerate fast, you press the pedal down hard, and the truck hesitates, the RPMs are not increasing with the pedal, the engine feels as if it stalling, and then, all of a sudden, the RPMs pick up real fast, the car lurches forward and you pick up the speed real fast. or, you are not picking up the speed real fast, the RPMs do not increase real fast, but increase slowly, and the steadily picks up the speed...

Emin, when you provide very laconic, telegraphic description of your issue, you get very BROAD answers that will send you on wild geese chase.

please try the take off sequence, document the behaviour of the car, and then tell us exactly what happens...