Re: misfire in cylinder #1 on 99 gc limited w/ 4.7l
A misfire can be caused by several things. The 2 basics are fuel and spark, either one missing or not at the right time can cause a misfire.
So could have to do with ignition coil, fuel injector and sometimes also a crank sensor or cam sensor. You could swap the ignition coil with an other, but since you don't get the check engine light at the moment, it probably won't tell you anything.
The PCM should normally react instandly on changes, otherwise it would be difficult to regulate the engine. So i won't expect any changes after a while.