Thanks for the suggestions. I don't think my car has a PEM (no pressure sensor on the fuel rail), but I'll see if I can find it.
I'll work on setting up for a vacuum leak smoke test next weekend.

I bought a 2005 xc90 T6 about a year ago, and have been having issues with starting that got progressively worse over time. First, it would be hard to start it hot. A couple months later, it would start 1 out of 5 tries, regardless of whether it was hot or not. A few months later and it will start o...