Experiencing crank and no start issues.

[aedir]

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 once in 50 attempts. In the event it does start, its idle is very rough; the tach oscillates between low rpm to 1.5k-2k (in a rhythm that makes it sound like it's gasping for air?)
I need some help and guidance to diagnose the problem (and hopefully fix it myself!)

I'll dump some info I think is relevant:
At the moment, I have crankshaft position sensor missing/faulty signal codes.
I am not sure if I have spark. I have checked by pulling out an ignition coil and grounding the spark plug while igniting, but nothing happens. I tested all coils by triggering them manually, and they seem to be working.
I've read that sometimes this problem is the aftereffect of servicing the transmission. I don't know if the transmission has been serviced.

Might not be relevant, but another issue that I experienced in the past was the ignition key cylinder bound up. I opened it up, following some random internet knowledge whereby removing a chunk of it and leaving it loose made allowed the key to rotate. Could a bad contact in the key be causing issues? It didn't seem like it made the issue worse at the time.

Parts I have replaced while trying to fix this issue:
- The timing belt, with its tensor and pulley
- Camshaft position sensors
- Crankshaft position sensor and its bracket (bracket was broken and had been repaired by a previous owner)
- Fuel pump (rail pressure was slightly under spec)
- The starter (because the old one sounded kinda weak despite having a full battery charge)
- MAF (had a code when I first got it)
- Battery (when I first got it, before winter just to be safe)

Thanks!

[cuhfs]

Here are a few thoughts. Not sure how valid they are for your issue.
1. Maybe a few issues at the same time exist causing the irregular starting once out of 50.
2.) Smoke test to see if there's vacuum leaks throwing systems off
3.) PEM (Fuel Pump Control Unit). I just replaced mine for a no start issue and that solved it. should be less than $50 used. I got mine from Erie VOVO

[ggleavitt]

Given all that you've replaced thus far, I would intuitively check the PEM (module that controls the fuel pump) but I'm not sure that you have one (MY04). I really don't want to send you down a rabbit hole but maybe have a look at this link for where they usually live- viewtopic.php?t=93506/

Key cylinder problem is reasonably common enough over time, I've had the cylinder replaced in both my vehicles at one point or another. Removing that broken chunk of metal (the wheel lock guillotine) will allow the cylinder to work fine until it binds up enough to warrant replacement.

[aedir]

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.