Did you prime your motor after installing the oil pump?
Yes. The motor was already lubricated and the oil pump was packed with petroleum jelly as per the instructions in my Haynes manual.
Crap, forgot about the code. Did you properly setup the new snychronizer when you installed it?
Following the Haynes motor manual instructions, I installed the synchronizer with the alignment tool (plastic cap that sits where the sensor goes) and the number 1 piston at TDC.
Just thought I should mention that all these problems persisted with both stock and replacement parts. I started with replacing the camshaft position sensor since my OBD2 reader said that was the problem. I then moved onto replacing the entire synchronizer with a fresh camshaft position sensor. I finally replaced the oil pump, pressure sensor, and sending unit. There have been no noticeable improvements.