Could this be a possible cause of my misfire?

 

Could be, but I have MSD superconductors and have them zip tied together at certain points so if it is a quality wire then that should not be your problem.
It is a good rule of thumb to always seperate the wires but with the technology of todays wires I dont think its mandatory.

 

I have my wires tie strapped together in many places to clear my headers, no problems in 10,000 miles, and they are cheap auto zone wires.