R34 Gtt Misfire when warm, coils?

[AnimeMasta]

Hey guys, my gtt will drop a cylinder after a couple of minutes of driving, but it will run fine for a bit longer when its colder. Sometimes it will switch back to normal for a minute, then go back to missing, its a bit random, but definitely seems to act up more when its hot/engine has warmed up. I get the three engine lights, (slip, tcs, and check engine) which means ignition circuit right? I originally thought it was the o2 sensor, so I just swapped that out with a new oem, idles nice but still eventually starts missing. The coils are still factory.

Car has 110,000ks on it, recently had new plugs, 1.1mm gap. I know should gap them to 0.8 but i figured that it wouldn't be the plugs since its more of an intermittent problem than a fouled plug. Boost is only slightly above stock - less than 10psi.

Ive done a fair bit of research and I'm pretty sure I need new coils, just seeing if anyone else has had the same problem and can pitch in their thoughts before I drop the money.

 

Thanks

[GTSBoy]

When do you get the 3 lights? Why not just put it into diagnostic mode and count the blinks?

Could be coils. Could be AFM or CAS connectors also, bad solder joints, etc. These sometimes act up as they get warm if they are not in good condition.

[AnimeMasta]

I get the 3 lights whenever it starts the misfire. I'll do diagnostic check and see what comes up. I've checked the AFM connector, its not that, I'll check the CAS.

[AnimeMasta]

Did the diagnostic, didn't realise how easy it is. Got code 12 AFM and 21 Ignition circuit. So clean the afm and splitfires then?

[GTSBoy]

4 hours ago, AnimeMasta said:

clean the afm

Maybe. Although it is so much more likely NOT to be dirty. It is much more likely to be a bad solder joint inside it onto the loom plug contacts. Google fixing that. Has to be cut open and soldered by someone who has enough of an idea what they're doing. And then siliconed closed again.

4 hours ago, AnimeMasta said:

and splitfires then

Again, maybe. The coils might be fine. It could be dirty/broken loom plugs here too. Swappsies with a known good set of coils is the only/best way to try to pin it on the coils or related wiring.

[AnimeMasta]

Thanks man, I'll see what I can do.

[AnimeMasta]

For future reference, it was the coils. Splitfires went in.