Not much Volvo content but need a shipper, east-west to LA. Advice?

Doubt you still have this, but if so, I'll take it, 24015. Thanks! Richard

Yes, look for torn intake manifold gasket near # 5 cylinder. Sounds like you have an air leak, a large one. Even more likely as you describe no such issues prior to taking on the PCV. Has to come apart, unfortunately. Take a long look at the intake manifold gasket as has been suggested.

I rarely use less than 91 octane gas. Especially after my valve rebuild. If your code comes back instantaneously after a hard reset, use your scan tool to erase it.

Lot's of info on this subject available by search, I asked a similar question a couple of weeks ago. Ultimately I pulled a battery cable, let it sit 2 hours, reconnected, CEL immediately appeared, off it went with my scan tool not back yet. Any other codes, or unusual behavior? If not try a hard res...

Smoke test for vacuum leaks if possible. Back to basics. Compression test look at plugs, etc. Ultimately, can be hard to tell about blue smoke. Put together a few more clues to guide you.

Are these codes related? Linked in any way?

96 850t runs fine. P0422 popped up a couple of weeks ago, cleared it. Returned today accompanied by P0326. No detected performance problems. Remind me where to look first? Thanks.

Pop the strut bar off, just takes a minute.

Great looking car. Wish I ever owned a car that used .5L oil every 4k km's, including brand new ones. You might make it easy and start with Marvel Mystery Oil, (? mineral spirits and ATF no fuss) directly in cylinder 2, let sit for 1-2 days, pull the fuel pump relay, crank a bit, add .5L to the fuel...