Hyundai Repair: Running rough, intake plenum, speed sensors

Question
found the code it reads P0305 misfire cyl #5, is it plug wires?
-------------------------------------------
The text above is a follow-up to ...

-----Question-----
Thanks for all your help, you were right on with the diag and fix, on the Trans for our car, change both speed sensors, Car runs bueatiful, but since then we encountered a new problem, driving at normal speed, came to a stop and check engine light came on, upon accelerating, car began to run rough, also rough at idle. After shutting car off for a few minutes, light went of and problem was cured, but only for a few seconds, same problem. After getting up to normal speed car smoothes out. Need expert help once again, thank you for response time.
-----Answer-----
There are many things that could cause a vehicle to run poorly.  The first place to start is to read the diagnostic trouble codes stored in the engine computer to learn what the computer has seen.  Chances are high that the stored trouble codes are related to your performace issues.

Answer
The code itself doesn't tell us why the engine is misfiring.  All the computer knows is that the misfire is occurring.  Based on your description, my primary suspicion is that you have some sort of secondary ignition system problem.  Unfortunately, cylinder number five is just about directly under the throttle body, so you cannot just pull up the wire to check.  

I'd recommend taking a known good plug wire and plug and attaching it to the #5 coil terminal and laying on the intake manifold.  Start the car.  If the plug sparks, you know the coil is operating normally.  The next step is then to remove the intake plenum and inspect the plugs and wires.  If I were going to this effort, I'd have new factory wires and good quality name-brand platinum plugs ready to install.