Weird top end knock/misfire

[93_jdm_fd]

I just had the engine built and is now in the car and running pretty good other than this weird knock/misfire type noise in the top end.

I can unplug #6 coil and the noise stops. As soon as I plug it back in the somewhat steady knock is back, unplug it and it's gone. All the other coils unplugged one by one will do the normal drop and stumble except for #6 coil. I switched #6 to #1 and I still have the same knock noise when I plug in the coil in #6 cylinder.

So it can't be the coil because it's now in #1 cylinder. I swapped out the coil harness for another know good one and it still does the same thing.

What could it be? #6 fuel injector, ignition timing?

[GTRADDICT]

Fuel injector. Do you have an after market ecu with individual cylinder tuning?

Edit: Fouled spark plug.

[93_jdm_fd]

I just put the spark plugs in. NGK plugs at 0.8mm gap. It only does it a idle, if I bring the idle up just by pulling on the throttle cap it goes away. It only has this knock/misfire at idle. I'm going to swap injectors around tomorrow and see if it changes to a different coil when I unplug it.

The noise isan't coming from a specific cylinder, it's just when I unplug cylinder 6 coil that the noise is instantly gone.

[MarusGTR]

I hope you unplug the corresponding injector when you take the coil off...

[93_jdm_fd]

What do you mean? So I don't flood out the cylinder with fuel? I only unplugged it for a few seconds, it should be ok.

[MarusGTR]

Yup that's what I meant lol cause a cylinder full of fuel is going to foul the plugs when you plug back the coil. That and it can contaminate and thin your oil.

[GTS4-R]

and itll wash those brand new cylinders before you even break them in

[93_jdm_fd]

Today I removed the fuel rail to see if anything had plugged it up. I also swapped #6 injector with #1 to see if my problem would change cylinders. It did not change. Now when I unplug #6 coil with #6 injector unplugged nothing changes. The noise and miss is still there. I don't know what else it could be. What other than a bad coil or injector would cause I misfire? I think the banging/knock noise is related to the misfire at idle. When I bring the rpm up to 12-1300rpm the noise is gone.

I tried to post a video through photobucket but it just comes up as a picture for some reason.

[GTRADDICT]

Hey I got a question for you... Is it a gtr or gts? If it's a GTS you have hydrolic lifters and need pressure to be primed. One is probably busted.

[93_jdm_fd]

It's a gtr and I"m pretty sure it's not valve noise. It's not a steady noise, it's like a rand


ohttp://www.youtube.com/watch?v=8S4DC0kfHz8m knock under 1600rpm and that's the only time I can hear it.

[93_jdm_fd]

There's a link to my noise problem. What's up with this site though, every button on my keyboard makes the page do something different??? Anyway the video makes my car sound like it's got all kinds of valve noise,bottom and noise. It doesn't. The noise I'm talking about is about half way through and it's like one of those morris code type noises and you can hear when I unplug #6 it goes away and as soon as I plug it in the morris code is back.