Weird misfire issue RB20DET

[WILLIAM_SKYLINEGTS-t]

Been having this issue for a little bit of time, misfire is weird in a sense that it isn’t a single time on each stroke of the motor. The best I can describe it is this pattern: running fine for a few seconds then misfires, good for another two and a half seconds misfires rapidly exactly three times in a row, runs good for another few seconds one misfire. This pattern repeats and continues. Only happens when the car starts to warm up after 3-5 minutes. Happens under load to with or without boost.

Just about every part on the motor is new. I also just replaced the motor because I decided it was time after seeing metal flakes in the motor oil since I first got the car. Any advice or help would be appreciated. If anyone gives a response I will likely be able to update and provide confirmation if it works relatively quick.

Motor swap was with another silver top RB20DET so the same motor, and the issues still persist.

[fontana dan]

Does this car set engine codes? Can you tell if it is going rich or lean when misfiring?
Engine could be losing a signal for spark or fuel injector.

[WILLIAM_SKYLINEGTS-t]

Very rich smell from exhaust. Stops missing if brake cleaner is put into the system, until the engine really warms up then it doesn’t matter. No engine codes.

[WILLIAM_SKYLINEGTS-t]

New update, car is throwing code 21: ignition circuit.

[fontana dan]

Went to see the service manual but it seems R32 is missing from the archives...
Not familiar with these cars at all...issues starting after car warms up means you could be losing cam/crank signal. Ignition module needs a reliable power and ground as well.
Have the spark plugs been changed?

[VStar650CL]

It's in there. See page EN-412 for a code 21:
https://www.nicoclub.com/service-manual ... Manual.pdf

The diagram is for an RB26DETT, but the RB20DET should be 2/3 of it.