Misfiring Mk4 1.8T

[Shleng]

Right the other thread got a lil messy and it wasnt even mine to start with. I have a Mk4 Golf 1.8T that is suffering from a misfire some of the time. It occurs at startup 95% of the time (Has done it twice when driving from cold). When it occurs the car only fires on what seems like 2 or 3 cylinders. It is possible to keep the engine running, and if i do so for 20-30 seconds, the misfire goes away.
I have had 2 breathers changed as they were found to be faulty (holes in both). Althought this seemed to sort the problem it has not gone away.
I have changed the plugs but this has not solved the problem.
I plan to clean the throttle body when i get over my illness as this has been recomended by Crasher. It has had a little clean but nothin thorough.
I have the VAGCOM diagnostic results also;


17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction

P1200 - 35-00 -

16795 - Secondary Air Injection System (B2) - Incorrect Flow
or Secondary Air Injection System: Incorrect Flow Detected : P0411

16684 - Random Misfire Detected - Any Cylinder
or Random/Multiple Cylinder Misfire Detected : P0300

16688 - Cylinder #4 - Misfire Detected
or Cylinder 4 Misfire Detected : P0304

17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) : P1297

16685 - Cylinder #1 - Misfire Detected
or Cylinder 1 Misfire Detected : P0301

16687 - Cylinder #3 - Misfire Detected
or Cylinder 3 Misfire Detected : P0303

17956 - Boost Pressure Regulation Valve (N75): Open Circuit : P1548

I have checked the functionallity of the Diverter Valve by disconnecting it and attempting to suck air through the 3mm tube. It seems to be functioning as i could not 'suck' air through it.

Just wanted you guys to look at the VAGCOM results and add your 2p worth

Cheers

[Shleng]

do these problems usually occur together? or does it sound like more than one cause?
cheers

[Nutty]

Im not familiar with your engine at all, but I once had a similar fault on a Vaux Astra, the cure was a new EGR valve, quite common on that make/model