[itschris]

You seem confident, so I'd trust your timing.

I'm still stuck on the vacuum leak theory. When in injection mode 1 (PI), LTFT + STFT hits 23ish. The car switches over to injection mode 2 (DI), LTFT and STFT is zeroed and climbs back to 22ish. Since those values are the same and open loop runs lean, I think the fuel side of the afr is likely correct and there's just too much air. If something was off with your fueling I think I'd expect to see a mismatch between fuel trims for each injection mode.

I would probably retest for leaks with brake clean. I haven't tried propane but that stuff is pretty dense. I imagine you'd have to literally touch the hose/nozzle to the leak to see any effect. Failing that, I'd test for leaks with smoke. Mostly to rule out the chance that you're forgetting to check somewhere.

Edit: I missed your post saying it runs with the MAF unplugged. I would double check your upstream O2 sensor is seated, and if it is try a new one