1998 Dodge 1500 Extended cab 4wd 5.9 Magnum motor Approx 115k miles. Mostly highway driving Check engine light, was coming on and then clearing by itself after a week or so. Started a few months ago. Was one most of last week, cleared on it own Saturday night, then came back on Sunday after a few trips. I can clear by disconnecting battery, generally returns after a few days of driving. Last code pulled a few weeks ago was 301 ? Cylinder 1 misfire ? Prior to replacing stuff mentioned below. I have not seen the check engine light flash. In an effort to resolve I replaced plugs, wires, cap, rotor and PCV a few weeks ago, no noticeable issues on old plugs, Occasional feel of a miss or stumble, generally when stopped, in gear and brake on. Tried pulling a few different plug wires, one at a time to see if there was noticeable change in idle. I was not able to notice a significant difference. Past history Catalytic convertor was replaced with after market (Midas) within the past few years ? old one was clogged and truck was not drivable at that time. O2 sensor (front, I think was also replaced at that time since the original was stripped)