You can't go by battery voltage alone all the time. A defective starter, higher than normal resistance between battery and starter motor can allow the voltage to look good and the engine still won't spin over fast enough to start. Not too many folks have the equip to actually measure the current the starter is pulling.
Relying on quick incomplete checks can provide false info and get costly if parts get thrown at the problem.

 

Check out https://charm.li and https://lemon-manuals.la for free service manuals.

 

OK an important update: I’ve been looking at the negative side of the battery and starting issue. The positive side had looked good when I replaced the starter. Cable was clean at the starter end. It ‘looked “ clean at the battery end where it bolts to the terminal. See picture. I removed the nut and the eyelet looked ok but I wire brushed it and cleaned with alcohol. Replaced it, tighten the nut and the starter turned much faster than before and engine started right up, although the rpm immediately went to 2500 rpm and then lowered to normal idle as it warmed up.
I figured the computer had to relearn its idle.

Good news with the slow cranking problem. Also with the rough running issue associated with the problem, I figured that that same dirty cable end might also go to the PCM or other engine controls after it leaves the starter.. And that may affect the cold running issue But why did the dirty cable end only affect the cold start and not warm start.

One more question. Still, when starting cold, there seems to be a “puffing” sound from the plenum area. It goes away after a few minutes. Also is it normal for the center of the 3 plenum runners to warm up faster than the other two?

Long posting but wanted to update those who have been helping me.

 

Good work, thanks for the update.

Now let's get to the remainder of a future possible problem. Why didn't you clean the battery terminal where it bolts to the battery posts. As you know by now, just looks can be deceiving.
Might look clean , but still have oxidation between post and terminal clamp.
If you did clean that part, my apologies !

 

Yes I did clean both battery posts and connectors as you suggested earlier in this saga. But not the one connect in the picture. Lesson learned on my part. Thank you.

Now if I can figure out the “puffing “ sound
I hear on startup. Could it be the EGR valve pumping exhaust gas into the plenum? BUT the EGR valve should be closed at cold. start up and idle.

 

It sure could !
You are getting to the point where I'm going to start asking you for advice !

 

Ground problem turned out to be poor contact at battery cables and mostly a bad starter. Cleaning everything and a new starter. Engine spins over and does start but runs poorly as described in my first long evolving post. Will update that one tomorrow.