Thanks guys! I just passed through emissions and got a check engine light literally 10 minutes after I passed the test. It's hilarious because the exact same thing happened with the 2000 M5 I had. I checked the cause of the light and it was a P3157 which is a cylinder 8 misfire. That's the only code and I got a misfire on that same cylinder this morning, so I suspect that it's an ignition coil. About half of the ignition coils on this X5 are the cheap eBay kind, including the one on cylinder 8, so I'm going to swap in a known good OEM coil and see if that fixes the problem. My spark plugs are all brand new and torqued down to spec. The misfire is very occasional for now.
Last night I did a little bit of digging around and found a Dice Mediabridge with iPod connection and Sirius installed behind the kick panel on the driver's side of the center console. It had the old 30-pin iPod connector so after a quick run to the local Apple store I got a 30-pin to Lightning adapter which allowed me to use it with my iPhone. It's a bit of a quirky setup but having an aux-in that isn't a tape adapter is perfectly fine with me haha. I do think the front tweeters are blown though, no matter what I play through them (from any source) there's crackling and distortion in the high end, even at low volumes.
I also tidied up in the trunk because it was a nightmare before. This is how the trunk looked when I went to disconnect the battery before diving into the chain guide project:
No wonder there was stuff banging around when I drove the X5 yesterday... After locating the proper nuts/bolts which were scattered around the spare tire well, I installed everything properly. It looks much tidier and the compressor is no longer flopping around.
I love quick little fixes like that, they're just so satisfying!
Today I ordered a new air filter, new cabin air filter, window shade hooks (some of mine are broken), and an aluminum water pump pulley. The current engine air filter is one of those lame K&N oiled air filters (not a fan) and I have no idea when the cabin air filter was replaced, so it's worth replacing both. The window shade hooks were extremely reasonable in price— they were a bit under $4 for a 4-pack of Genuine BMW hooks. I was honestly expecting them to be like $30. The water pump pulley is mostly intact for now, but when I was reassembling everything I saw that it was starting to chip away a bit so I figured I'd replace it with a sturdier aluminum one.
I'm not a big fan of those kidney grilles with the painted silver slats, they look like they're trying to imitate the facelift style. Eventually I'll get some all-black grilles from ECS Tuning. I also find it hilarious how my co-worker's new Challenger on the right has angel eyes but my BMW X5 doesn't... for now, at least.