Cylinder Misfire

[thezenvan]

I bought a 2013 Nissan NV2500 V8 with about 60,000 miles on it last week from a car dealership. When I bought the vehicle I used a OBDII reader to check the codes on it and it came out clear. After I test drove I checked the codes again just to make sure nothing popped up and it was still clear. Everything overall looked fine so I bought the vehicle and drove it home (about 160 miles away).

 

I'm going to use the van to do a conversion so for the most part it's been either sitting in my driveway or I drive it about 5 miles back and forth to work on it so besides the initial long haul it hasn't been used that much so far. Yesterday just for the hell of it I decided to test it again with the OBDII reader (something I probably should've done right after completing the drive back from the dealership) and it popped this pending fault: P0303 - Powertrain Cylinder 3 Misfire Detected

And shortly after the malfunction warning light came on. After googling around I saw a couple of possible solutions but they range from a few hundred dollars to a few thousand and I rather not spend that. The vehicle is out of warranty and was sold AS-IS.

 

After talking to someone knowledgable he suggested that the fuel that was previously in the van while it was sitting at the dealership might have a bunch of gunk in it and I should try using STP to clean it out and see if that helps so I got some STP and filled it up. So far it hasn't worked since the light came on again, I cleared the code again and I'll see if it comes back but I wanted to know if there are any other ideas that don't involve spending a lot of money on it.

 

Thanks

[mk1_62]

STP is a waste of money. BG44K was recommended to me by several mechanics. I use it in all my cars every 20k miles.

 

It's pretty cheap on Amazon, or you may have a local dealer.

[thezenvan]

So far the issue hasn't come back but I'll look into the BG44K if it does, thanks

[mk1_62]

Probably not a bad idea to run a can anyway. I have to warn you it might set off the check engine light. I had it do that on my Camry, it fouled the EGR filter with gunk it blew out.

[thezenvan]

Update: I guess I spoke too soon and the STP didn't work as well as I thought. The code came up again and as well as the warning light. I'll go try some of the BG44K and if that doesn't work I'll probably order a replacement spark plug to see if that fixes the issue

[thezenvan]

Another update: I ended up replacing the spark plug on cylinder #3, it looked pretty nasty but the misfire hasn't shown up again yet.

 

I got a comment that the color on the head of the plug might be because of an oil leak in the oil valve stem or head gasket so I'll have to look into that

[andy_george]

Whoa, yeah, that does look a little ugly. Never seen a plug like that....

 

Keep us posted!

[ASD Dad]

Ouch!  That is one ugly plug.  That is all ash deposits from really bad fuel or oil burning.  You are correct it could be from a bad valve guide seal.  I can absolutely see why that would be misfiring!