Hesitation at High RPMs Options

[captb]

Hi all, I just started having this problem 2 days ago. and its on and off. the car hesitates as if one of the cylinders isnt firing and it only occurs at rpms above 3k and when acclerating fast or when going up an incline. initially i thought it was the spark plugs but they look alright and so do the distributer cap. I was watching the rpms and i dont visibly see any changes at low and high rpms. so then i thought it may be the gears going bad but it occurs on all the gears, and it cant be the clutch because i dont feel any slipping or anything. the car was running a little low on oil but even after i added some it still occured. The engine light came up and im getting codes 12 and 13. which means i am misfiring right? im starting to think it may be my intake, and its misfiring because its running rich and not getting enough air when the engine is pushed. i installed the new filter (some generic brand) just a few months ago. I will continue to try and figure this out but just wanted some input from you all.

thanks.