Another Cold weather starting problem

Hi all
New guy posting
Great site, very informative
2000 Jimmy, 4.3 W engine auto trans, 109500 mi. Cold weather starting problem.
Followed MT advice and pressure test the fuel pump. Here are the results.
Key on not started 60 psi
Engine started idling 58 psi
Pinched off return key on not started 64 psi
Driving & accelerating between 56 & 58 psi
I guess the readings speak for them selves. Change the fuel pump?
What seems funny is that the truck starts no problem above 14’ F. Anything colder and I have to plug in the block heater I assume to keep the injectors warmer. If any one has any other suggestions please let me know.
Thanks

Make sure the fuel filter is not restricted. You still need at least one more piece of data to complete your diagnosis. Key on, engine off, fuel pump running shows 60psi, which is at the bottom of the spec. After the fuel pump shuts off, pressure must remain above 55psi for 3 to 5 minutes. If the pressure holds, the pump is faulty, (unable to build sufficient pressure). If pressure does not hold, it could be either the check valve in the pump is leaking, fuel pressure regulator is leaking, or lines under the plenum are leaking. Post your results and we'll continue, if necessary.

GM does not publish any "engine running" pressure specs, all pressure tests are done with the engine cold and off.

Pump stays @ 60 psi for over 10 min.

How old is battery and how many cold cranking amps is it?

When's the last time the plugs, cap, rotor, and wires were changed?

Son in Law had a similar problem.....no start when cold. I tried everything, fuel pressure OK, etc. What I found was no 12V on coil, no spark. I ended up installing a switch under the hood that would supply 12V to coil so he could start it. After starting you could turn the switch back off. He only needed to do this when it was below 40 degrees or so, otherwise in summer it was OK. Weird.