Low RPM Missfire

Firstly I'm not sure if it's a misfire or not, but (usually in 4th) at 1100-1800 ish rpm the car feels like it misses, at first I thought it was the A/C but it seems to do it regardless of the A/C, the car seems fine in other gears and at higher rpm, I will most likely try some new plug wires on Saturday, but it does not make sense to me that only one gear at a specific rpm would do this, a bad wire should miss at all rpms (the 4th gear is most likely due to the longer amount of time spent at those low rpm's because of the sluggish accel at those revs)

Car Info
2002
Ford Focus SE
Zetec
5 Speed Manual

Any help is very appreciated!