My el xr6 felt sluggish off the line and had a bad stutter when accelerating off idle then the distributor failed so replaced that and found the cap and rotor were in very bad shape as well as the hall sensor failing after that things improved alot but it still feel a bit sluggish at low rpm and it feels like its got a miss ever few seconds. Ive installed aftermarket extractors and the o2 sensor (which i replaced when i did the dizzy) is only sensing off 3 cylinders instead of all 6 like it would from the factory. Would this be likley to be causing me any issues or does it not matter?

Edit: i installed the headers before the dizzy failed so im not sure what it would have been like with a good dizzy and the factory manifold.

I wouldn't think the O2 would play much of a role with car performance. It is used to detect levels of O2 in your exhaust and adjust the fuel/air mixture.

Have you checked/replaced your spark plug leads? They could be faulty causing poor spark and under load can fail and give you a miss.

Check for a vacuum leak some where.

Plus I'd be checking the timing is set correctly post the dizzy replacement.