possible fuel regulator fault

[RS6BRIT]

Hi guys, I need a bit of help and advice.

My car went into the garage yesterday for a full service. When I went into pick it up it had developed a constant misfire which the guys were trying to fix. I had a full set of coilpacks fitted along with new plugs and we (they are close friends) quickly decided to switch back to the old ones to see if that sorted it. It got better but didn't completely disappear. The car also needed an MOT so it went onto the ramp and when the tester put the prob into the exhaust he noted that bank 2 was running very lean, too lean he said. He then went round to the front of the car, and pulled off the connector to the fuel regulator valve on the fuel pump. Nothing happened. He put it back on and pulled off the same connector on bank 1 and the car dies almost straight away.
I took the car home and it started to miss again and showed the EPC light.

Using VCDS I checked and got code 2177 and 2179 system too lean off idle.

Today I did a vac leak test and found a leak on the now redundant power flap line, so it capped it off at the top. That sorted I went out and drove the car for about half an hour. The car drove fine with no faults showing on VCDS, however it stalls when I pull up after using full throttle !?

I also pulled off the connectors as mentioned above and had the same results as the MOT tester along with the code P129B- Fuel Pressure Regulator Valve; Bank 2 (N276) open circuit. This code is obviously because I pulled the connector off, but I would have thought that it would have stalled out but didnt.

I was going to try switching the 2 sensors over and trying again to see it stalls out when i pull the now reversed connectors off, is that possible ? or should I just get a new regulator?

any help would be great guys as I dont want to keep driving it if its running lean and doesn't know it.

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The car may have adjusted its calibrated idle point with the small vac leak. Now that you have fixed it the engine isn't quite getting enough air.
Granted, long shot, but easy to fix so worth trying - just use VCDS to clear all codes on all controllers and that may help. Also worth looking at throttle calibration process on rosstech site.

2177 is indicating the long term fuel trim is approaching or at it's maximum configured level of adjustment. Clearing codes should reset the fuel trims so a good starting point.

[RS6BRIT]

Thanks Ads (hope thats your name !!) I'll give those a go. What are your thoughts on the pulling the connectors off scenario. I've checked ETKA and found that the whole pump will need replacing as you cant just change the solenoid. I've found one on ebay from an '08 plate so might just take a punt on it. My reasoning is that as both connectors on both pumps should have the same effect, then why when one is disconnected it kills the engine whilst the other does nothing ?

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Depends how the two regulator valves are wired. They may be asymmetrical - would need to check elsawin