First well go over the hard idle. Sounds to me that your coolant temp sensor may be bad, also the IAC may need a cleaning, check the housing on the IAC and the IAC itself if you notice any maring fix it, also the pintle on the IAC should be moving freely. Also clean the throttle body
for the missfire you may have a bad fuel injector, is the cylinder getting bright blue spark? If so check hte compression on it and clean the injector.
Hope this helps.
Tuesday, December 11th, 2007 AT 4:55 PM