Hi this silvarado has a two part problem that may or may not be related. If you cruise the truck at 2000 rpm in third gear ( Manual Trans ) it has a rythmyic cut out / surge that the best way i can decribe is that it feels like you are driving a small 4cyl car...

FIX posted 7/29/2011

iATN Members:
Login to view full TechHelp request
Auto Repair Pros:
Join iATN to read this TechHelp request
Vehicle Owners:
Find a nearby iATN member to repair your vehicle