Please bare with me as the newest vehicle I own is an '87 and I've never owned anything with OBD2. I picked up an '06 Altima 2.5 cheap because it has high mileage and a starting issue. I needed something 4-door and easy to keep a car seat in. Most times it starts right up, other times it might run the battery dead turning over and I have to get jumped off but it always eventually starts. It had two codes when I got it and now it has four codes. This seems like a car I could spend hundreds of dollars throwing parts at it and it's just not worth the investment. I don't care about the high miles and if it lasted a year or two I'd be happy but since it's so new it has to pass emissions to get it registered. Could any of these codes cause it to be so hard to start intermittently? P0420, P2A00, P0300, P0303. The last two just started a couple days ago. The first two are O2 codes and I don't think they do anything on startup. The car runs perfect after it starts and everything on it still works. I'd hate to scrap it and cut my losses but it might be inevitable.