Won't Start after being on gentle slope
 

I have an 04 XC70 that has an odd issue. After parking on a quite gentle slope, nose downhill, it won't fire. It cranks just fine, however. It also has about 3/4 of a tank of gas, and had only been sitting there for about an hour or so. It also did the same thing after I had had it jacked up on the front passenger side (checking on a grinding noise, I need a new right side CV axle) on my otherwise flat garage floor. Again, nearly a full tank. Each time if I let it settle back to level for an hour or so (off the jack in the latter case, let it roll to a flat spot in my driveway in the former) it will start again without issue.

Any ideas on root causes? I'd hate to have this happen when I am out and about and need it to start right away.

After browsing around some more other people seem to be pointing to the fuel pump being shot. Any other thoughts before I pick one up?