[Spuds]

Well, I found A problem... Not sure if it is THE problem. One of the fuel rail pulsation dampers is missing the adjustment screw.

In other news, all the injectors seem to be working fine under low pressure at least. Ran some carburetor cleaner through them while pulsing and noticed no difference between them. Microfilters on the inside looked intact and clear too. Might swap them around when I put it back together just in case I still have the problems. At least then I'll isolate it to a specific injector or something else on cylinder 5.

Edit:. Debating whether to get a right side fuel rail for ~$80 (in addition to damper for ~80) because of all the rust. I got it cleaned up a bit but needing a chisel to remove some of the rust isn't confidence inspiring when looking at a pressurized fuel tube that goes next to the engine...