I've only had my evo 8 for 500 miles or so but when I picked up the car from the dealer the battery was completely dead. I know for a fact it was fine before that. It does have gsc s2 cams that have been on for about 3k miles. Any chance the dead battery could have messed up the ecu flash?

 

Nope, the tune in the ecu will not be erased because of a dead battery. Most likely it's trying to relearn the idle.

What are the exact idle issues you having?

 

The afr at idle stays around 14.5 when it idles fine, but it occasionally jumps up to 16 or down to 13. A few times its almost died it idling because it was so off. Driving around its ok and under wot its fine. It just does it at idle. If I hold the idle at 1300-1500 rpms there's no problem but when I let of the throttle and it goes back down to 900 rpms or so it starts bogging again.