I have an 03 durango 5.9l v8 2 wheel drive that constantly has a cylinder misfire check engine code. I have changed the spark plug, and spark plug wire and the problem returns later. At times there was moisture on the spark plug and other times it seems dry and needed to be regapped. I do not know why this is happening. Does anyone have any solutions or suggestions. Thank You

Double check that the spark plug wires are not crossed.

May have a faulty fuel injector on that cylinder.

check compression

The next thing to check for is a bad distributor cap. The terminals are notorious for corroding. Might as well change the rotor, too. And, as mentioned earlier, also check on the injector. Where I work, we have a fleet of Ram vans, and pickups with the 5.9/360c.i. engine, and they are a constant headache with misfires, and no-starts, especially in wet wheather. I've been doing alot tune-ups in the past year for the same problem.:runaround:
Mike

Open the hood at night with the motor running a lot of times you can see what is occurring.