Below is a lengthy discussion on the #1 cylinder misfire topic...There are two additional topics that will be helpful at:
Note: Be aware that the #1 cylinder misfire code is a catch all. A good friend phoned me from King of the Hammers last year, sharing that his late (2004) TJ Wrangler 4.0L Rubicon engine would not idle on a hot restart. The code thrown was a #1 Cylinder Misfire. Before calling, he had visited the local auto parts store for an OBDII code read and ended up buying an injector for #1 cylinder. That did not cure the problem, so he bought a coil-on-plug ignition coil pack. Neither changed the rough engine idle after a heat soak...We talked about the TPS (throttle position sensor), which usually throws its own code. He then shared that placing a welding glove between the throttle body and the hot engine seemed to prevent the rough re-start. We bounced this characteristic back and forth, and ultimately the IACV Solenoid turned out to be the problem. All of this over a #1 Cylinder Misfire Code that turned out to be engine roughness due to a defective IACV Solenoid! A new IACV Solenoid ended the problem, and the PCM stopped throwing codes...This is a situation where diagnostics experience and troubleshooting pay off. Throwing good money after bad, doing the "parts replacer" approach based upon PCM/MIL codes, can be wasteful and futile in some cases.