would the engine show any signs of cracked coil packs, like rough idle or misfire.

 

If you have rough idle or misfires, you should have some codes stored.
Have Advance or AutoZone read them out.

 

I was getting a cylinder 6 misfire. I ended up replacing vacuum lines. Had to pull intake for one of them. Then i did plugs and plug wires it ran worse than it did before. Didn't throw any codes so the only thing that was left was coil pack. I took one off seen a crack so i started checking the rest they were cracked to. Now runs like a new one.Not saying anything is wrong with yours but there easy enough to check.

 

I had more problems removing and installing the spark plugs than any problems with the wires . A couple of 1 1/2" wobble extensions sure help on those rear plugs