TTS - engine problems - engine shuts down/revs go up/knocks when shift. Help plz.

I have a Sep 2008 TTS and I had problems with it lately. Car will shut down when I am idle and I put first gear (Automatic gearbox - so it can be D, S or pedals gear change) to move. This would happen randomly. I tried replicating the problem by taking the car to the exact spot that it did it before and repeating exactly what I did before (full stop, release break, and press gas) but it would refuse to replicate it.

It did it to me a few times and other symptoms are:
1) Sometimes when 1st gear is engaged but car is not moving the revs would come up up to 1,500-2,000 2-3 times and then go down again to 800.
2) When it changes gear, especially from 4th to 3rd and from 3rd to 2nd (either in auto mode or pedals) I feel a "hesitation", a knock in a way to the way it slows down. So I can be pressing stop and car will change from 4-->3-->2-->1 and every time the change happens the car kicks a bit.

The audi garage found a problem with the presseure valve for the fuel system (showed up in the diagnostics/fault code) and changed it. It was a 5 min job since is located just under the engine cover. But since then (a few days ago) the car did the shut down problem and the "hesitation" problem two times.

I run a diagnostics check after garage changed the sensor (before taking the TTS to the AUDI garage this morning) so I can have a clue what shows and these are the errors I got. I will print a copy for the garage and give it to them and hopefully they will know where to start looking. Anyone has any idea what work needs to be done and how long it usually takes for them to fix it?

Address 01: Engine (CDL)

2 Faults Found:
000135 - Fuel Rail/System Pressure: Too Low
P0087 - 002 - Lower Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 2
Fault Frequency: 3
Mileage: 47382 km
Time Indication: 0
Date: 2011.05.13
Time: 19:43:24

Freeze Frame:
RPM: 819 /min
Load: 20.8 %
Speed: 0.0 km/h
Temperature: 87.0°C
Temperature: 45.0°C
Absolute Pres: 1000.0 mbar
Voltage: 13.589 V

004506 - Fuel Pressure Sensor (G247): Malfunction
P119A - 002 - Lower Limit Exceeded
Freeze Frame:
Fault Status: 01100010
Fault Priority: 2
Fault Frequency: 1
Mileage: 47657 km
Time Indication: 0
Date: 2011.05.16
Time: 22:19:30

Freeze Frame:
RPM: 820 /min
Load: 20.8 %
Speed: 0.0 km/h
Temperature: 87.0°C
Temperature: 45.0°C
Absolute Pres: 1000.0 mbar
Voltage: 13.589 V

Readiness: 0000 0000

Address 03: ABS Brakes

1 Fault Found:
01309 - Power Steering Control Module (J500)
008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 5
Mileage: 47664 km
Time Indication: 0
Date: 2011.05.16
Time: 22:37:49

Freeze Frame:
Count: 192
Count: 9029
Count: 8212
Count: 45312

Address 16: Steering wheel

Part No: XXXX
Component: E0221 H06 0030

1 Fault Found:
01044 - Control Module Incorrectly Coded
000 - - - Intermittent



Just an update on my issue.

Garage replaced High pressure fuel pump. Problem did not go away. Original high pressure fuel pump was put back.

Garage replced electric fuel pump, problem appeared again, original part was put back.

Car is garage now trying to figure out what to do next.

ANYONE WITH SOME HELPFUL INFO PLEASE DO TELL AS I AM VERY FRUSTRATED WITH THIS SITUATION.



Country: Cyprus
Make: Audi
Model: TT Quattro S
Year: 2008
Area: Engine
Engine: TFSI 2L
Mileage: 47700 km
Part: SW: 8J0 907 115 Q HW: 8J0 907 115
VIN: TRUZZZ8J891014403
Expertise: I have some knowledge

Already Tried:
Changed Fuel Pressure sensor, front fuel pump and gas tank with no success. Garage then installed back the original pumps but kept the new sensor on the car.