DI seal problem?

[pariggi]

Good afternoon,
I’d like to get your opinion on an issue that’s been worrying me a bit.

GT86 first series, ECU firmware updated to ZA1JA01G using Tactrix at around 30,000 km (the car now has almost 67,000 km).
Every now and then, very sporadically—let’s say after 50,000 km—when starting cold in the morning, I noticed a few small pops, not too loud.
No issues while driving.

Over the years, the frequency of these pops has increased… let’s say 8 times out of 10 (always and only during a cold start) it gives two or three small bangs.

At around 61,000 km, I decided to monitor the issue more closely after experiencing a really loud POP.
I used Protec P1101 injector cleaner, and after just 50-60 km, at the next startup, the issue was completely gone. (

).
Wow… so it was just some deposits after all! In fact, I don’t drive it that much, and the issue has always and only appeared in the morning when cold. If I use the car multiple times a day, the problem never happens.

Unfortunately, after about 5,000 km, the issue came back.
This time, I used Tunap 974 (thinking it would be more “aggressive”), but it didn’t help. Now, the POP is noticeable at every cold startup (here’s another video).

Honestly, I’m not experiencing any other issues while driving… When properly warmed up, I can floor it from 2,000 to 7,000 RPM in second or third gear without any hesitation or pops.

Do you have any advice?
Do you think it could be the well-known direct injector seals?