Looking for misfire reasons P0301, P0303 and P0305 2007 Chevrolet Silverado 4.3L

Question

We have replaced plugs that were burned up swapped coils on bad cylinders with coils from good cylinders. We have removed the Vortec assy, had the injector and poppets ultrasonically cleaned, and still show misfires on 1,3,&5 no apparent vacuum leaks. The truck has 70k miles.

Answer 1

Did you replace the wiring that connects to the coil because they go bad? did you check the intake manifold gasket? it has to be related because its only in bank 1

Also have you check compression? you can also do intake manifold flush