Rb25de Misfire

[Wordsmith]

Hi, so I've been getting some violent misfires sometimes at low revs. Its like that for a couple of minutes at low revs then it runs fine. Pulled the fault code and it's error 21, P1320. Googled it and I read that the most likely cause is to do with coil packs. http://engine-codes.com/p1320_nissan.html

I don't think its the coils themselves because I had them replaced with JJRs just a few months ago when I had another error 21 and a misfiring engine. And its run perfectly since then up until a week ago. I didn't replace the spark plugs then, could it be those this time? The odometer reads 135000 and I don't know if the previous owner replaced the sparks at any time. I also read somewhere that sparks can go bad from being run with bad coil packs, and I was doing that for quite a while last time I got the error code.

Thanks

Edited September 13, 2015 by Wordsmith

[Wordsmith]

Over the last few days the misfires have stopped and the engine is running fine once again. The check engine light has also stopped turning on. Could the misfires have been caused by a bad batch of fuel or something?

[Wordsmith]

So I had a huge misfire last night waiting at a red light immediately after exiting the motorway. The car was shaking like an old bus. The misfire continued until I put it in third gear at about 4000rpm, after which it stopped. There were no more misfires when I came to the next red light.

Last time I took the car in to service I was informed that the rocker cover gasket is leaking. It occured to me today after watching this video that leaking oil could be fouling the sparks, causing the misfires.

Has anybody ever had a misfire from oil leaking onto the sparks?

Edited October 4, 2015 by Wordsmith

[Wordsmith]

So I just got it back from the mechanics. Replaced the rocker cover gasket and got the sparks and coils cleaned. I didn't get to drive it far yet but so far so good, there was no misfiring at idle and I didn't lose power through the low-mid RPM ranges. The engine light is still on but I haven't yet connected the consult to get the code. I'm hoping the uncleared code is Error 14 Vehicle Speed Sensor since the speedo doesn't work. Hopefully the misfires stay away!

I was told that the PCV valve and hose need replacement. How difficult is it to replace it? I'm a total novice at anything mechanical but I would like to start learning, starting with replacing the PCV valve and hose.

Edited October 14, 2015 by Wordsmith