I have a 2011 Chevy Silverado with the 5.3l that is running really bad has no power. The weird thing is that the scanner is not showing any fuel trims long or short. It's not the scanner have tried from other shops. Everything else shows on the scanner. Tried a new ecm same problem.

 

Any ideas

 

If the scanner you are using provides fuel trim info with other vehicles, and another scanner will not work with your vehicle. it wold be safe to conclude there is a problem with the vehicle.
What do you get when you try to run a health check function with the scanner?

 

I've used 3 different scanners all 3 show no fuel trim short or long 0.0% graph stays at 0. The 02 sensors are showing .005 they are working and reading properly.