If it's running like it's supposed to, there's no need to replace it. I have an 87 Silverado, and it's never had the injectors replaced.
Never, it is designed to last the life of the engine and is normally replaced when the engine is overhauled.
Not until the truck starts bouncing. are the shocks go to leaking.
The P0282 code indicates a problem with the cylinder 8 injector circuit, often related to low voltage or resistance. If replacing the injector did not resolve the issue, you should check the wiring and connectors for damage or corrosion, as well as the injector driver circuit in the engine control module. Additionally, testing the resistance and voltage at the injector connector can help identify any electrical issues. If necessary, consult a professional for further diagnostic assistance.
Every 16,000 miles the fuel filter should be changed. I do it every other oil change. The 2006 has a change fuel filter reminder on the DIC, but I don't know how it calculates the change interval. Fuel filter change is critical on the duramax because of the extremely high pressures of the common rail injection system. Any water or debris can cause major injector damage.
should only take two hrs. and cost of inj. maybe 40.00
If you needed a gasket and they replaced it then yes you would be charged for the gasket.
The fuel filter is a permanent filter mounted inside the fuel tank. No service is required.
Never, normally it will last the life of the engine.
You will never need to. It will out last the truck it's self.
idle should be aroung 900 iin park then when in gear should idle around 650 or 700
Could be an injector spraying at below the pressure that it should. Or a head gasket. Check your radiator for milky fluid, if not you can determine the bad injector by loosening the nut at the injector line/injector until the sound of the engine changes. The one that does the least change to sound/rpms is the bad one. You can have it tested at your local dealership.
You may not have sufficient fuel pressure. The 2.2 should have 41 to 47 psi and the 4.3 should have 60 to 66 psi.