2003 durango 4.7 p0300 random misfire

Just started getting a p0300 random misfire code on the durango a couple days ago. pretty sure it isn't moisture related since it started on a nice sunny day. it was running pretty rough so it was obvious that it was misfiring. I changed the plugs since it was about time anyway, and they needed it and I cleared the codes. new plugs (put in the oem champion copper plugs) didn't make the problem go away. The engine still ran rough and the code came back. 2 of the plugs looked like they may have been fouling a little bit. they were a fair bit blacker than the rest of the plugs. I went ahead and changed the coils on those two cylinders and reset the codes again. Still runs rough and the p0300 came back. where do I go from here? I am not getting any specific cylinder codes so it makes sense to me that it isn't one or two cylinders not getting spark. Any thoughts?
Thanks!

Lombard

Look at it at night when running. See if you can see any arching from any wires or the coil. You can even mist it with water in a bottle to see better. If nothing I would check each wire for spark by grounding a spark plug to the block. I am guessing that your plugs are good if new and that you checked for correct gap. If you have spark then it sounds like your ignition coil or coil packs are good and your ICM You can have that checked at auto zone if you want. Next is to change your rotor and Distributor cap. Check for wear on the posts on the cap. If it looks like they are wearing on the sides then you should check the distributor it's self. MAKE SURE you don't have play in the rotor after you take the cap off. You should not be able to move the rotor to much. like 1/32-1/16 of an inch. Mine just went bad and I was able to move it about a 1/4 in that caused my random misfire. Also what year is your car?

Thanks for the reply. It's a 2003 with a 4.7. No distributor or traditional plug wires either. It's coil on plug. Not sure if there is a way to test the individual coils or not.

Oh yeah, there's tornado's out there tonight, so I'll be waiting til tomorrow to check it out in the dark :)

After troubleshooting and not getting anywhere I took it in to a shop here in town. They cleaned out the fuel rail on the even side (cylinders 2,4,6,8) and said that 6,8, the ones that looked fouled to me, looked like they were getting water in them. They said it is a head gasket. I have heard from several places that the head gaskets on the 4.7 are a pain in the rear to change. How bad are they really? Worth doing myself to save on the $1700 I was quoted?
Thanks.

i have the same problem why do they think it is a head gasket?

they thought it was a headgasket because it was fouling on plugs 6 and 8. I was getting fuel and spark to those cylinders, and the pressure tests were coming back good, but they only thing they thought it could be was a head gasket.
Unfortunately for me it was much worse. It ended up being a broken camshaft for me. Hope yours isn't that bad.

What's common with 2,4,6, and 8?
Why did the gaskets go bad on bank 2?

A plugged Cat will cause random misfires, over heat, damage seals & head gaskets.
Shorted oil or too much oil will also cause gaskets & seals to go bad.

1) Have a back pressure test done on your catalytic converter bank 2.
2) Compression test cylinders on bank 2.
3) Visual inspect and replace any bad seals & gaskets.