I just recently installed a header and cat delete pipe on my type s. I had a cel pop on after it was all installed... (ended up being upstream o2 was unplugged):bash. so i plugged it back in and the cel went off. After about 200miles it came back on, now it will randomly go on and off by itself. ive unhooked the neg battery cable and the ecu fuse under the hood. It will stay off for a little bit then its back on... should i just replace the front o2????