P2293 - Fuel Pressure Regulator 2 Performance

I’ve been getting this code intermittently over the past couple months with no perceived/obvious performance loss. The CEL is cleared and it comes back a month later or so. Recently the CEL has crept up more frequently but usually during casual driving and not during WOT runs at the strip.

Most research that I’ve done points to the cam follower and/or fuel pump. However, my understanding is the design has been changed on the EA888 engine and the cam follower design ( four lobe roller) doesn’t require constant attention (I’m at ~45K km). This leads me to HPFP. While logging a variety of driving conditions I’m seeing a Fuel Rail Pressure range of 536 to 2416 psi (37 to 166 bar). Problem is I can’t seem to find “standard” values. AFR during WOT is 11.20 or roughly 0.76. MAF reading is 262.22 g/s. All reasonable for K04 tune. Short term fuel trims range from 10.2% to -7.8%.

This is all on APR’s 93 K04 tune using 94 Octane Petro Canada.
Car mods can be found here:
http://audirevolution.net/forum/index.php?topic=2129.0

Any ideas on where else I should be looking or am I missing something from the above data?