Not my idea of a first post but I just picked up a 2000 trailblazer that had a miss when the engine was cold last week, after it gets up to temp it runs fine, and the check engine light is was on for p0420 but hasn't come back since I cleared it. Odd thing is the misfire is centered around 2k rpm and only part throttle. That's not it though, today is the first dry day in a week and it's ran fine all day. This has me kind of stumped, could it be a moisture problem with the coil?