Hello, i swapped a 2008 6.2(l92) into a 04 Silverado and i barely cant keep it idling. I think the x-link is causing the problem but not sure. The x-link is the newest 4.0 (?)version designed to work with the truck throttle body. First time i started it, everything worked just fine and took it for a ride and nothing was failing except the truck needing a tune for this 6.2. Once i drove it a little more and started logging, it all of a sudden died and couldnt get it to start. Then i unplugged the x-link and plugged a stock tb in and it started right up. Then i reinplugged the x-link, it started up, but i get a code(U0107). I cant delete the code and i have no idea whats causing this problem.

 

Not intimately familiar with that motor, but usually my mystery idle and start problems on my trucks come from the iac/tbs systems. Just had the iac act up on my 5.3 and turned out one of the 4 leads had a small fray in it. It didn't show up on a continuity check either. Fixed the fray and good as new. Hope that helps..