89 Pickup w/ 3VZE no power for a short time after cold start

Truck has been doing this for some time now. Sometimes, the truck starts fine, and will idle, but if I try to drive it before it warms up good, it lacks power when I start out in first gear (manual trans). Sometimes it's so bad that it will stall when I try to start out, then when starting it will run for a few seconds and then die. It will do that numerous times, then eventually continue to run. Usually when it starts and dies, if I try to give it throttle, it will die. Today I was on a hill when it was hard to start, I hit the gas and it backed down the hill, then it continued to run.
More times than not, it will start and idle fine, and run fine.
I checked codes this evening, I got 21 (O2 sensor) and 43 (no start signal to ECU until engine speed reaches 800 rpm with vehicle not moving). The O2 sensor code may be old, I had a wiring problem last summer, I may not have cleared the code after I fixed it. I pulled the EFI fuse for a while, then test drove it. When cold, if I pushed the accelerator fast it would hesitate (not in gear, just revving engine). Hesitation was gone after it warmed up. Open loop vs closed loop? I checked codes after the test drive, nothing.
It usually doesn't fire right away when I try to start, it generally cranks for 2 or 3 seconds after I hit the ignition switch, then starts.
I believe spark plugs have been replaced fairly recently, should be good.
I haven't checked fuel pressure, I'm thinking that might be a good idea.
Other than described above, no hard starting. Never had it fail to start.
If I understand the code 43 correctly, I should have a lot worse problems if there were a hard fail.
No issues once it gets warmed up some.
I just tested the TPS, AFM, and O2 sensor. All test good.
Anyone got any experience or thoughts they'd like to pass along.
Please and thank you.......................