Ok I have 03 silverado I jst bought a 5.3 bored to 5.7 with forged rods and pistons from summit. Anyways I put a stage 2 centrifugal cam cuz I have small blower and bought afr heads.anyways I paid someone to tune it and every time we started it .it would go in to reduce power mode loss communication throttle body. I have nick Williams 103 throttle body with that damn xlink. He thought it was xlink but we figured out that if we turned head lights off it wouldn't do this. truck ran fine b4 new engine I do have aftermarket led headlights never heard of this anyone ever been in situation and fixed it please please let me know thanks