The surging in my engine is still bothering me but I'm going to ask my random question of the day and see if it makes sense...
Before I started changing boost pipes, I was trying to take my intake manifold off to clean it. In the end, that wasn't possible, but one of the things I did do to get access was to take the TIP out. Because access is really tight, I had a few issues getting the pipe seated back on the turbo when I put it back together - especially with the VW hose clamp/spring clip setup.
Here's the random question - if the TIP isn't on tight or isn't seated properly and is maybe leaking air, could that be what's causing the issues I'm having?
Thinking back, I never had that much of an issue before, so I'm wondering if it might be something I've done - I didn't drive it much between taking out the TIP and getting the new boost pipes fitted, so it is making me wonder.
The main reason I'm asking is although it won't do any harm to check, on the ARL engine, it's a faff taking it all apart to get access, so I'd rather not have to do something if I don't need to, but I do have some time this week to do it, so...