P1367 Cylinder 5 - Ongoing code with no symptoms

[mr16valve]

Hi all. Here is some background info:
01 S4 with Apr software, snow stage 3, BW K04, RS4 intercoolers, RS4 fueling. The car is very mechanically sound.
Had my car to a European auto specialist for a host of driveline maintenance (all fluids changed, apikol diff mounts, tire rotate/balance). Anyway upon checkout he gave me a bottle of BG 44K professional injector cleaner. He said to add this to a half tank, which I did. Few days later I took a spirited ride along the blue ridge parkway. My foot got planted in the carpet inside the tunnels & the car began to have a strong miss in higher rpm. Check engine flashed for a bit then stopped & went off. I drove the car normally home & had no issues. Vagcom pulled these when I scanned: P0300 & P0305.
I replaced the Bosch F5DPOR plugs, all coil packs with German made Beru & both ICU with German made Beru units.
The plugs were textbook of how a plug should look. The coil packs & icu's appeared to be original.
The car runs fantastic again but now gives a P1367. If I clear the code it comes back within minutes. Again, it runs strong with no detectable misfire or any other hesitations.
Where should I look now? Injectors?
Thanks for any help.

[mr16valve]

Pic from that fun day....

[LJS]

FWIW-
I had a similar issue with my auto -It turned out to be an issue with the Evap Purge Valve...Something to look at...
PS- car looks GREAT!

[mr16valve]

Thank You. I'll do some more searching around to see what that brings up.
I have a N80 on order anyway. I have close to a grand into this problem; another $75 won't hurt.