Ok, so I have a Howell TBI, headers, and a single wire o2 sensor. I'm experiencing the same problems as the OP. At first wasn't happening at all, now as it heats up. Is the suggestion here to go to a heated sensor? If so, how would I convert from a single wire to multiple? OBD code also throws a 44, which is "Oxygen sensor voltage was under 0.25 volts for 50 seconds of closed loop operation."