So my car starts up, but idles very roughly (almost stalls its self out) and when i try to reverse or move it will stall out. But if i drive it around for a bit the check engine light comes on and off. but it wont stall after i drive it for a bit. Someone i know had this happen to them and it ended up being the pcv valve and it took out the cat. Just wondering if you think this is it or a belt or alternator or something?