2001 Durango, 4wd with 4.7 engine. just over 100k miles. Truck has been running fine. about a month or so ago I noticed when I first started it, white smoke would come out of the exhaust like most care do in the winter. It does go away once the engine warms up. Not sure if this is related, just thought I would mention it..

About 2 weeks ago while driving, check engine light comes on and I notice it started running rough. Pulled the code and it was 306.
What I've done so far:

First I changed the spark plug in #6. Plug condition noticibly worn down. No change to probem.

Then I changed all the plugs and swapped the #6 coil with #8. Cleared code. Still ran rough and code came back as 306. So I believe coil is fine.

I'm running injector cleaner through the gas now, but I'm leaning towards thinking it's not just a dirty injector, since the roughness and code started at the same time.

Any ideas what I shoud try next?

 

P0306 Cylinder #6 Misfire

You have replaced the spark plug, but did you use the same cheap Champion Copper and gap the plug at .040???

Next seeing that you swapped the injector and the problem in #6 didn't go away I would begin to question the wiring to that coil pack or the harness to it.

Next I would think a cam sensor or crank sensor could be your issue.

Or something else you could try is remove the injector and tape a plastic bag on it and turn the motor over and blow out that fuel rail. There might be something floating around in there.

 

he swapped the coil not the injector,

i would try swapping the injector if the cleaner int he tank doesnt fix it (swap it to a different cylinder than you did with the coil), after that i agree with hydra you will have to start checking wires.

 

Thanks for the input. Yes I have NOT swapped injectors, only the coils. Seemed like an easier job. I will swap injectors (with a different cylinder) tomorrow. I'll let you know what happens... Thanks again.