Not sure about the 2nd o2 sensor but mine did the exact same thing when I had my carb rebuilt, I traced it down to the Idle Cut solenoid, it's where the other 2 wires on the carb go, not the choke and not the vent, should be on the rear passanger side of the carb. Hook up to the batt directly, easiest to do through the plug itself, with some long spare wire. If it dosen't click then ya need a new one, it's probally stuck open, which will flood the motor when you stop and cause it to die. I perfected the art of 3 foot driving when I was dealin with this little number <img src="/forums/images/graemlins/lol.gif" alt="" />