my cousin has an 01 4x4 with auto and it is completly stock.yesterday he said that after the truck warmed up and you put it in gear that it wouldnt move until you got the rpm's way up.then it would take off.and anytime he let off the go pedal and the rpm's dropped way down.it would do the same thing.thanks for the help guys dont no much about 24 valves and autos

 

My first thought is fluid level (that's being very gracious)
More likely it is extreme slipping and that means rebuild time (that's unfortunate truth)

Make sure the fluid is checked in neutral

 

maybe tq converter failure? has he checked the fluid? just taking shots in the dark

 

i dont no if he has checked anything yet but i thought maybe t/c was messed up but the more i thought about it.i dont think it is because it only does it taking off in first all the other gears work fine thanks for the input though any other ideas