Auto Parts: automatic stalling out., honda owners, computer figures

Question
I have a 99 honda accord 4 cyl. sedan lx. I recently just replaced my header and full exhaust with an aftermarket one. At first i didnt have an extension wiring harness to plug my primary O2 sensor in, so when i started the car i assumed that was why i got a check engine light. I started driving the car around and it started to sputter and seem like it was going to stall. Usually this only happens when i am at a stop. On some occaisions the car actually does stall. This usually happens when i am in R, N or D. (i have an automatic) After installing the wiring harness and got the O2 sensor plugged in, I realized that i had a leak where i bolted my Header on to the second half of the header which led to the catalytic converter. I can feel some air seeping from there. I have not had a chance to take it a part and fix it yet. However i am wondering if this leak has anything to do with my car stalling out. Thanks!

Answer
    The problem is most likely related to the time you spent driving the car without the oxygen sensor hooked up.  You definitely need to fix that leak.  There is a secondary oxygen sensor aft of the converter, and it needs to have all of the exhaust flowing past it.  In fact, although you can feel exhaust leaking out of the pipe when you crawl under it at idle, I wouldn't be surprised if it was sucking air in at higher speeds.  You need to erase all of the codes from the computer, and then drive the car for an extended period of time (40 or 50 miles) until the computer figures out what's going on and reprograms itself.  While you're at it, make sure that nothing else got disconnected while you were working on it, and that everything's properly connected.  If this doesn't straighten it out, take it to a Honda specialist (not necessarily a dealer) and get them to put a scanner on it and check everything.  And don't worry, they're used to Honda owners screwing with their cars, it's sort of like a disease.