p0172 Help Complete With Vag Readings

[grubby]

Trying to make that dastardly light on my dash go out... This is a 99 NB 2.0 AEG engine 5 speed manual.

Have MIL/CEL checking codes with vag com reveals a 16556/p0172 rich code but no others, engine idles fine and drives with no noticeable symptoms. I Did have a few vacuum leaks but I believe all have been fixed now, but maybe not. Block 032 o2 trim readings are -18% and 11.8%, ran some injector cleaner through at the last fillup with no change. Also ran a WOT 2nd gear maf test. Highest level recorded was 73.96 g/s from memory it seems the g/s should be closer to 90? Thanks in advance for any help. I hate to replace parts yet without some certainty that they are indeed bad.

scan info below

Chassis Type: 9C - VW Beetle
Scan: 01,02,03,08,15,17,19,26,35,46,54,56

-------------------------------------------------------------------------------
Address 01: Engine
Controller: 06A 906 018 JE
Component: MOTRONIC M5.9.2 HS V01
Coding: 00000
Shop #: WSC 00066
1 Fault Found:
16556 - Fuel Trim: System Too Rich: Bank 1
P0172 - 35-00 - -
Readiness: 0000 0001

-------------------------------------------------------------------------------

[beej]

Sounds like o2 sensor to me?

[grubby]

After getting the fuel pressure tester I finally got to test the pressure at idle. It is higher than the service info says it should be. At idle the pressure is supposed to be 2.5 bar and mine is 3 when removing the vacuum hose to the fpr the pressure is supposed to rise to 3 but mine goes to 3.5 instead. As I understand it this sounds like the fuel pressure regulator? Could this still be caused by a vacuum leak at this point? Seems like the vacuum is there when disconnecting it and it makes a .5 bar difference when applied/removed. Guess it's probably time to replace the fpr. The only other concern is that somehow the fuel return line is blocked somehow but that seems unlikely.

[grubby]

So I replaced the FPR and if anything it actually increased the pressure slightly at idle. How would one test the return line, it doesn't seem pinched or anything. I just replaced the fuel filter which was a mess, one of the connectors didn't cooperate.