Just bought 2006 Equinox-Canister purge valve??

[sixpack_sid]

I just bought a 2006 Chevy Equinox and cylinder #5 is showing up on the check engine light. I replaced the spark plug and accidentally broke the canister purge valve vaccuum line. Cheap plastic junk!! I tried to repair it with some epoxy but when I started it up, it ran really rough! $40 for a new one and now the engine light is still on. I see a cap on the vacuum line it goes into. Do I need to unscrew the cap and bleed the system or something? What is that cap for??
Can anyone help me out??
Thanks,
Sid

[sixpack_sid]

I checked the codes today and it's showing a misfire on cylinder 5. I changed the spark plug and reset the battery. The light came on again with the same code. Any ideas on what I should check next?

[Charger RT]

don't work on many gm's these days so unsure of the setup in 06. if the cap is green its part of the evap system. its a test port.
the following is a list of things that will make a cylinder miss
plug (already done)
plug wire, coil pack or coil on plug what ever it uses.
fuel injector
wiring to injector or coil
injector or coil drivers in computer
cylinder has issues
on a miss like this I will swap the plug into say 1 and the coil to 3 reset and see what cylinder resets the code. 1 would be plug 3 would be coil 5 would be injector or cylinder or any of the wiring computer issues listed above. on the fords we do work on we have gotten to the point of replacing both coil and plug if the plug looks good. 80% of the time the plug alone doesn't fix it.
Tim