What is the normal reading on the temp guage when engine running after full warm-up. Mine reads one slash-mark below the mid point slash on the guage. Seems to run fine but for some reason I thought in past it ran a little cooler but could be mistaken.

 

That's where it should be; just a tick below half.

 

Yeah 1 maybe 2 below half...

 

and stable in all running conditions!- needle should stay 1-2 lines below half

 

Most temp gauges are really glorified idiot lights. Between certain temps it will hold a specific reading (usually about mid point). Only when the temp goes over a prescribed value will the gauge move up. This is to minimize (eliminate) fluctuations and swings on the gauge. Most drivers would run right to the dealer because everytime they sat in traffic and the temp went to 3/4 or higher they would think something was wrong.
So unless it goes toward the red your fine.

 

that may be true for honda and other cars about moving guage
BUT
the TL guage sits dead solid=
be it at idle and fan running, or 90 degrees 80 mph going uphill at 5000 feet altitude and ac on full blast

two honda techs pronounced a ziners car fine when it had swinging temp!
iirc that was a bad thermostat in the end-
but honda person said all the hondas do it-- so your acura must too! WRONG

IF your TL guage does anything but come up to just below half within a few minutes and stays there all day,,then you have a major problem

 

Exactly.
A few years ago Mazda did a silent recall to replace temp gauge sending units as the "enthusiast" real time temp readings sent owners to the service department in droves...