I head P1684 might be a ground issue....factory grounds are freaking horrible. Really, you guys don't know how bad it is until you change them out. Check those out. There is one where your engine connects to your battery tray, the passenger side near the motor mounts and two from your headlights

 

Bosch is good but if u want performance i would go wit MSD 8.5mm

 

UPDATE:

I finally got around to changing the ignition wires. I tried to get Bosch but they didn't have any in stock, so I got the more expensive brand. Anyway, I changed it last night. Took about 5 minutes. Decided to go to the gym and...

Huge difference. No more cylinder misfires! Car definately runs a lot smoother. About gas mileage though- It seems to have slightly improved, but it still isn't above a satisfactory level. Maybe a few more miles now, compared to the 13 I was getting. I'll see what engine codes dissappeared a little later and post because I'm in church attire and I don't wanna play with the greasy battery wire. Thanks to everyone that posted the suggestions.