04 Durango 5.7 p0300 multi misfire

I have a p0300 code coming up on the comp. The motor runs fine untill it gets wet. rain/carwash I have tried to spray each coil with water and could not get it to misfire. Then I brought out the water hose and sprayed it top of the motor this found the misfire. This thing has 8 coils and I realy don't want to replace them all. My Queastion is there some tihing else that could be causing the misfires. :runaround:

I am not familiar with the Durango since I have just picked up an 02 SLT Plus.

It could be the plug, wire and or coil. (There are others but these are the most common)
What cylinder(s) are misfiring?
I assume you have two coil packs?
Are the multiple misfires on the same coil pack? If so, it is probably that coil pack.
Can you swap the packs and see what happens?

If it is one cylinder, swap a plug and then a wire to see if the misfire moves to a new cylinder.

Basically, without diagnostic equipment, it is trial and error.

Thanks pkucan but this thing has 8 coils and sixteen plugs wires. I do have a scan tool and just keep getting p0300 as the code this is muitl misfire. replacing 8 coils is a big deal the price is somewhere around $360 or in the area. I my just get the wire but that most of the time will not fix this type of trouble as it happens only when it getts wet. I was just hoping that there might be a wiring harnes or something that could be causing this be for i started repacing coils. Tks

Thanks pkucan but this thing has 8 coils and sixteen plugs wires. I do have a scan tool and just keep getting p0300 as the code this is muitl misfire. replacing 8 coils is a big deal the price is somewhere around $360 or in the area. I my just get the wire but that most of the time will not fix this type of trouble as it happens only when it getts wet. I was just hoping that there might be a wiring harnes or something that could be causing this be for i started repacing coils. Tks

fireplow,

Just had the same issue on my 01' Durango from the no. 5 cylinder. What I'm currently doing now is I rested the light on the dash and am currenly driving it to see if the light is activated again. It might just be a fluke. Our engines are electronically controlled heavily BUT their not fool proof. Take it one step at a time and don't rush out to spend that money when it might just be a very small issue. For now just see what happens.

rimfire,22

Tks this a muilt misfire not just one (wish it wascould find it easer) I was told it could be the crankshalf sincer any body know if this could cause the p300 code. tks

Hey,

I had the same problem with my Durango. I have the same year and motor. Found out there was an update on the cowl, but that didn't work. What worked was the o-rings for the intake were leaking. Take some spray of whatever, i used water and spray it around the intake while its running. I couldn't believe it, but yeah. Fixed the issue. No more stalling or missing during the car wash and raining.

Best Regards:cool:

Axe_1, I am having this same issue. What exactly did you do to fix your problem? Did you replace the o-rings? Any help would be appreciated.

Axe_1, I am having this same issue. What exactly did you do to fix your problem? Did you replace the o-rings? Any help would be appreciated.

govchicken,

The dealership replaced the o-rings on the intake. This was a agreement when i bought the Durango. Pretty sad i had to troubleshoot the problem. But this is a hard problem to find. Everyone goes for the electrical first like i did, but then found out the intake was leaking, pulling the water into the motor causing the misfire.

when you say "replace the o rings on the intake" are you talking o rings on the intake manifold? I am getting the same issue on my durango, my post is a few posts down. I finally broke down and took it to a mechanic. He at first thought it was clogged injectors on 6, and 8 (I had noticed the plugs were black like the fuel wasn't getting burned right when I changed the plugs and so I put on new coils, but that didn't fix the issue) He took the fuel rail off and cleaned it but the problem remained. He said it looked like water was getting in there and so he thinks "it must be the head gasket" are the o rings a semi easy/cheap job? I'm being quoted $1700+ for the head gasket job and would pretty much try anything within reason before doing that if I can.

Everyone,

Prior to spending tons of money. I would do a pressure check on each cylinder. This will tell you if the head gasket, valves, or pistons are not sealing like they should. I have found a website that shows the picture of the o-rings i think they replaced and i found a manual how replace them. Doesnt look to complicated at all. Here is the website i found

http://northernautoparts.com/ProductModelDetail.cfm?InventoryId=110445

Hope this helps

Thanks for the info, it looks like I am getting coolant into 2 of my cylinders though so I am pretty sure it's a head gasket. Funny thing is that my compression is good on all 8 . . .weird, but I don't know what else it could be.

Thanks for the info, it looks like I am getting coolant into 2 of my cylinders though so I am pretty sure it's a head gasket. Funny thing is that my compression is good on all 8 . . .weird, but I don't know what else it could be.

If your losing coolant, are u adding coolant? Either you will burn the coolant or see it in the oil. The most I have seen in the past on vehicles is the head gaskets leak into the cylinder chamber. If u smell the exhaust, you can usually smell antifreeze or even see white smoke.
Curious, is your Durango misfiring all the time or just with a carwash and rain?

That's what makes it even stranger, I hadn't lost enough coolant that I needed to add any. I started tearing it down last night and I had no coolant in my oil, and no oil in my coolant, so I was happy to see that. Also, it completely quit on me so I can't tell if the exhaust has white smoke or not. The durango is the wife's kid hauler so I don't drive it much. It was misfiring all the time, not just when raining etc. I am thinking that it is leaking into the combustion chamber. I'll know for sure in a day or two when I have it torn down that far.

OK, so I didn't mean to hijack this thread, I had started one similar, but I found out what my issue is, and it isn't a head gasket. At least not JUST a headgasket. I popped the passengers side valve cover off and was going to pull the heads tonight, but instead I found a broken camshaft. I'm off to start a new thread. ;)

I am having the same problem on the same vehicle. The O-rings? Do you mean the O-rings on the plug wires? Any way to clarify? The link mentioned above takes you to intake manifold gaskets. Any help would be awesome. Thanks