P0204 Injector Circuit Malfunction and Cylinder Misfire

Hey guys - just created an account on here, but I was a member on the mazdaspeedforums for quite some time. I'm trying to see if anyone would have any advice on how to best approach the P0204 injector circuit malfunction and P0304 misfire. The two CELs only come up during cold starts.

Background:
- 2013 mazdaspeed3 with 85k miles
- I cleaned the valves about 3 months ago, at the same time I had the injectors professionally cleaned / CS injector seals installed / EGR deleted / VTCS deleted / PCV replaced / new NGK spark plugs gapped properly
- When I first put it all back together, I had a high pressure fuel leak at cylinder 4 (same one that is giving me issues now, coincidence?). For some reason one of the washers on the injector didn't get seated correctly (see pic). Had to disassemble and replace the washer. I used Sil-glyde to help seat fuel rail onto the injectors. After that, everything ran perfectly fine. Had no CEL's for 3 months. The cold starts were a bit rough, but I expected that with the VTCS delete.

- Fast forward 3 months later after the install, the car starts up as it usually would (cold start) and then it starts to misfire. Each time I get the exact same code for cylinder 4 injector circuit malfunction and misfire.
- Usually by the third time I shut it off and restart it starts up fine like nothing happened.
- No issues or CELS when driving, it only happens each morning on cold starts.

I don't want to make assumptions and waste time and $ trying to find the issue, but I have a feeling that the injector might be causing this issue? I have a new injector on it's way, but any advice on how to diagnose this issue to make sure it's not the wiring harness or something else?

Thanks for reading and any advice on how to proceed is appreciated!

 

Where are in you FL? I've got a spare used injector you could test with. May be cheaper than a new one.

 

I'm located in Melbourne, FL. I have a new OEM one coming for $187, so not too bad. But still annoyed since 1 out of the 4 that I sent for cleaning failed the tests. So I had to buy a new one then... and now 3 months later I'm having to buy another lol.

 

I am also in Melbourne. Have a whole set. Buy my old ones (however many) I pulled at ~75k and save a few bucks?

Edit for the question mark.

 

Have you figured out your issue? I appear to have something similar going on.