Checking for vacuum leaks tomorrow

My car has developed the fault below, its a 1.8t DBW AUM engine which is basically the same as the AUQ fitted to Leon Cupras. I'm looking for common areas which cause these problems, so I can focus on them. Obviously I'm going to have to strip bits off and do visual inspections, but any tips from people who have solved this before would be great.

17544/P1136/004406 - Fuel Trim: Bank 1 (Add): System too Lean

Possible Solutions according to Ross-Tech's Wiki:

Check Mass Air Flow (MAF) Sensor - Brand new one fitted showing good g/s reading.

Check Fuel Pressure Regulator - Brand new vacuum hose fitted between manifold and FPR. How do I check the FPR?

Check Fuel Pump - If all else fails I'll look at this and change the fuel filter.

Check Intake/Exhaust System for Leaks - I'll check these over the weekend.

Check Secondary Air Injection for Leaks - Any tips on known places where leaks occur?

Check Vacuum Lines for Leaks - I've checked most of these including all the plumbing around the N249 etc, and the DV which is fine, can anyone suggest any known week spots to particularly look for?

It's very quiet in my thread, hopefully some people will offer advise tonight.

Found the problem, this pipe connects directly to the inlet manifold, so will cause vacuum/boost leaks. I repaired it and now th engine runs very well.



The hose location (hose not fitted in photo)