Hyundai Repair: 2000 Elantra miss fire, intake manifold gasket, hyundai elantra

Question
My 2000 Hyundai Elantra runs rough and my code reader says that cylinder #1 is miss firing. I replaced the spark plug and gaped it, checked the wires and they are good, replaced the injector and the coil pack, and even tested the compression and that is good yet it still runs bad. At this point I am open to try anything.  

Answer
Can you feel the misfire?  Can you tell me the circumstances under which it occurs (idle, acceleration, low rpm-high load, only after driving awhile, only when wet outside, etc.).  Additionally, how did you check the plug wires?

Ultimately, a misfire can be caused by anything that will prevent the normal power from being delivered by a cylinder.  While most misfires are caused by the secondary ignition system, there are numerous other possible causes:
-- anything which would result in low or no compression in the suspect cylinder
-- leaking intake manifold gasket
-- faulty or clogged fuel injector
-- low fuel pressure

If you can answer the initial questions above, that may help me point you in the direction of the cause or lead you down a diagnostic path do find the issue.