in need of a little help

i know this is not not a 3000 gt but could anyone help me wit this i have ask this in the chevrolet from but maybe some can help me in here? when i am driving down the road at any speed and rpm are at 1500 and i give it more gas it just jurks and stumbles untill i push the gas all the way to the floor. i have a 2000 chev silverado with a 5.3 4X4 and autotrans just did 60k tune up.. 4x4 serv, plug, wire, ect

maybe you'd ought to get the transmission serviced. My dads van used to do the same thing and it turnned out the tranny was going bad, cost 80 busck to repair it.

do you know what was wrong what did they replace?