The cBV diaphragms get old with age and can develop holes, that will inhibit boost. It’s a dissasemblyto diagnose , though. Not an easy job on turbo XC due to access. I think VIDA says remove turbo.

Also the MAF sensors get covered with small dust particles. This reduces their performance. However, just cleaning with the MAF spray doesn't really change much. I managed to clean mine with a small brush and there was a good difference on how the engine felt - mine is the non turbo MAF so much easi...

If CBV is leaking, would I see/feel anything on the vacuum line coming off of it? Yes. Disconnect the hose from the TCV side and do the mouth vacuum test :) CBV is a royal PITA to remove on the car, but still doable (I did that a month ago). Also, can someone clear something up for me (I've not wor...

I don't know about those graphs. 2550 hPa = 37psi, which is wildly off. Not that the graph line is hitting that, just that it makes it subject to the part of my troubleshooting routine where I toss it as not useful. A $25 boost gauge is invaluable troubleshooting this. It'd be pretty high on my list...