My 2002 dodge dakota 4x4 has 168k miles on it, and recently it runs rough for ~30 seconds after a cold start. This problem has gotten progressively worse, and issued a p0305 code last night after it ran very rough right after it was started. The code means that there is a misfire on cylinder 5. The power seems good, and doesn't seem to have this issue when it is warm. After about the first 30 seconds to a minute, it seems to idle and run very smoothly. It doesn't do this every time it is started either. Since it was about time to change the spark plugs, I changed those and the ignition coils a few weeks ago. This did not fix the problem. Do you have any idea what this might be? From searching on the Internet, it could be a fuel injector, O2 sensor, PCM, or a bad valve or piston. Some of these seem unlikely since this only seems to happen after a cold start. If an O2 sensor were bad, wouldn't this result in another or different code? Might this be a fuel pump issue?