Audi A3 1.8T AUM 2003 (petrol)

Fault codes:
P1297 17707
Pressure drop between Turbo and Throttle (check D.V.!)

P1137 1745
Fuel Trim Bank 1 (Add): System too Rich - Intermittent

Had this in before Christmas with the MIL on then cleared, running out of time so said bring it back in if the MIL comes back on which it did yesterday


I have done a smoke test to see if there is a leak between throttle valve and turbo, but no leaks

What i have noticed is that after idling for 2 minutes the EVAP solenoid starts to tick quite loudly which did not seem right when just ticking over, using VAG-Com the valve opened to 31% for about 2 minutes then shut off

Is this normal when idling?. If the EVAP solenoid opens at the wrong time could it cause a pressure drop or rich mixture?

Peter