Ok so last night me and a friend put my new Greddy header on at his house. All went well except for the o2 sensor is welded right above the collector of the header and it didn't fit into my o2 sensor connector and I didn't have the tools to take the old one out of my downpipe. Anyways as I'm driving home there is no o2 sensor in and sitting at a light I almost stall out because my rpm's drop so low. I give it a little gas and it goes back up, and I continue driving. About 2 minutes later I'm going like 50 and all of the sudden my car dies, and my lights dim. I pull into a random street and pop the hood. The o2 sensor connector that I had tucked safely away had come loose and fallen too close to the header and melted. After that I tried to start the car and see if I could make it home but nothing happened. I managed to get towed from a friend to the shop and that's where it's sitting right now. Long story short, is simply the o2 connector the reason it's not turning over? Or did something bigger than I realize happen?