Alight I baught a 98 Durango 3 weeks ago, its a nice truck and ran great. I noticed it chugs a little at idle so I was planning on doing a tune up to it today. Well when I was goign to drive it in the garage the check engine light turned on for the first time since I got it. I checked it with my genisys scanner and got a cyl 6 misfire code 0306. I checked the plugs and they were way past shot, so I proceded to do plugs, wires, cap, rotor. Started her again and ran the exact same, cyl 6 still misfiring, you can unplug the wire and the motor will not run any different at idle.

The thing that baffles me the most is the misfire goes away completely above 2000 rpm, but is clearly there at idle. My scanner shows this in the live data. I am stumped.

Here's what I have done sofar. New plugs, wires, cap, and rotor. Swapped #6 injector with #2 one and no change. Did a compression test and all cyls within 5% of each other. Tested the injector and they all test out the same, tested the signal from the computer and its pulsing normally.

SO I am lost. Anyone that can help would be awesome.

Mike

 

I thought I replied ot this post already... but maybe not

My first thought leads me to believe that either you have a ****ty set of wires - the 5.2/5.9 run best on OEM wires.. also, what kind of plugs did you put in? Platinum plugs will cause rough idling, Champion truck plugs work the best, and same with Autolites, I can't remember the pert # for the aotulites...

Let us know what you replaced your ignition components with and we can give you a better guess as to where to look for problems

 

I used autolite plugs and mopar wires, and rerouted the wires according to the TSB.

 

problem fixed. It was a vaccum leak from the gasket on the bottom side of the plenum. I didn't know there was a gasket there until I pulled it off. The old one had squished out and I replaced it with a new metal gasket and ran perfect.

 

You mean the plenum gasket on the bottom of the intake manifold. Awesome you found it!


I don't like the autolite plugs! I hope you didn't install platnum?

Also what about installing a cap and rotor. I like the brass contact type.