Chrislind2, kd7ctv and tehhax- I hope you all know the original poster was asking about the LFX or the 3.6L DOHC found in all 2012+ impala, not the 3.5L and 3.9L. The push rod engines are simple to do a tune up on. You don't even need the W-body ratchet either though it does make life easier lol
The LFX is a little different though, the plastic intake is molded to cover over the rear bank and makes it impossible for you to clear out the cylinder #3 and #5 coil packs, you can snake out cylinder #1 coil pack though.
I guess the laugh is on you Chislind2 for not being able to read the post correctly, I do this for a living/work at a professional shop.