shaking bad

I have a 04 trailblazer and it start to shake once started I replaced sparkplugs . I hade the truck looked at by on guy and he said I need a valve job then had my buddy check it out with a camera and he said I don't need one everything looks fine he's going to check out the fuel injecters. Any help would helpful thanks....

I have a 04 trailblazer and it start to shake once started I replaced sparkplugs . I hade the truck looked at by on guy and he said I need a valve job then had my buddy check it out with a camera and he said I don't need one everything looks fine he's going to check out the fuel injecters. Any help would helpful thanks....

Make sure he knows how to do proper testing.
Got any check engine lights on or flashing?
If so get codes and post back codes.
How many miles on it and what kind of plugs did you install?
Any cylinder misfires on it?

Your post is foggy, Did the miss start after the plugs were done, if so recheck your work

inspect the coils for carbon cracks along the long rubber boots. I had to have a boot replaced 4 years ago on an 02. Not sure how the dealer did that.