I have a bone stock 05 LLY that I got about 2 months ago. Shortly after I bought it I had to replace 2 injectors. When they were diagnosed by the GM dealership here, they said that they had to do more than usual to diagnose them as bad. I replaced them and the truck runs a lot better but still not 100% right. There is a bit of clatter while cruising only under moderate to slight load. Also, there is a little smoke at any throttle that clears up when cruising but if you punch it the black smoke is very thick. I'm also hearing a weird chirping sound at around 1500-1700 rpm that I cant figure out. The typical exhaust whistle on idle due to the VGT is not there but the truck has stock exhaust. Any thoughts?