So DomT was kind enough to VCDS my car at the J&H meet. This is what he found:
Address 01: Engine Labels: 06F-907-115-AXX.lbl
Part No SW: 1K0 907 115 A HW:
Component: 2.0l R4/4V TFSI G00 0070
Revision: --H01--- Serial number: VWZ7Z0D1164430
Coding: 040300031C070160
Shop #: WSC 00004 210 87564
1 Fault Found:
004195 - Fuel Pressure Regulation: Control Range Not Reached
P1063 - 002 - Lower Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 0
Fault Frequency: 5
Mileage: 161826 km
Time Indication: 0
Date: 2000.00.00
Time: 09:39:43
Freeze Frame:
RPM: 3003 /min
Load: 28.6 %
Speed: 120.0 km/h
Temperature: 66.0°C
Temperature: 19.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.224 V
Readiness: 0000 0001
No other errors.
Ross-Tech wiki does not contain this error. Googling is not too helpful; someone on a 2.7TDI Audi reported this issue but was resolved by regenerating the DPF. Not really applicable for my case.
The only other thing I found was on a guide to errors in an Audi A2 1.6:
http://vwforum.vwforum.ro/index.php?act=attach&type=post&id=178112As likely causes, this is what it says:
Air in fuel system, fuel system leak, fuel lift pump, fuel bypass valve, fuel pressure control valve, high pressure fuel pump.
Air in fuel system or fuel system leak seems unlikely to me.
Possibly some more VCDS logging is required; anyone have any further thoughts what it might be? JKM checked out my cam follower and said it looked fine. I presume the HPFP is running alright; I'm on my stock map right now and this occurs.