I have a 2002 Buick Century and never had any trouble with it. Rarely drive it. All of a sudden it cut off on me on the interstate. Been driving it all day. It starts up fine but then after about a minute it will begin to choke, sputter, and rough idle then cuts off. Towed to mechanic and he said he got a code P0300 and it had a bad misfire and needed 6 spark plugs, 6 spark plug wires, and 3 coil packs. Replaced those, doing same thing. Then on other bad advice told to clean idle air control valve, replace MAP sensor, replace fuel filter, clean throttle body, and replace MAF sensor. None of these worked. Finally towed to dealership for diagnostic on code P1635 and after testing every wire and 5 volt part on vehicle, they could not determine the issue. Said they had to call the manufacturer for help, but are still waiting on callback, as they are on strike. They said that when it's connected to their machine, it runs fine, but once disconnected it starts the sputtering and dies again. They then determined it was the O2 sensor that needed replacing and that would get the vehicle running again but they couldn't guarantee the check engine light would turn off. I explained the tags will require renewing in Dec. and would not pass emissions with light on. Replaced the sensor today and it is still doing the same thing. Will start up then die after a few minutes. At this point we have dumped a few hundred dollars into this car but don't want to trash it. The day this happened, I did fill up the tank with gas, but had been driving the car all day with no issues. Also, the odometer is not working in car. Told the cluster panel needed replacing, but hasn't been done yet. Called another mechanic friend and was told that it could be the PCM. I can't afford to pay for more guessing.