This car has had a mind of its own when idling and warm. Drives great for about 10 min then idles too low (I usually put it in neutral at stop lights because of this). However, in past several days, the idle climbs to 1000, 1500, sometimes close to 2000 when it's been on the road for 20-30 minutes or so. Up until yesterday no codes (at least in module 4) were present.

Yesterday I took it for 50 mile ride down freeway. About 30 miles in, the SES came on and I was actually happy to see it as weird as that may sound. Maybe something to give me a clue as to what the problem is. The SES did not come on when I restarted the car to head home. It did come back on later in the drive. After I got off the freeway, the idle went low then started to raise up (1000-1500 or so) then back down. Then the car almost died and actually "ran on" or "dieseled" for a couple seconds. Never completely shut off though. The SES light turned OFF at that point.....

Pulled the codes this morning and got the H32 EGR valve or circuit code. While retrieving the codes I also noticed there was no C12 code.

The SES never comes on when the idle issues are present. Is the EGR valve causing all the idle problems or is that another issue? I should add, the fuel pump is pretty loud when the idle issues are present. (the pump is new)

The other codes that came up:

C25, H25 courtesy lights
H72 LCD dimming open
H74 LED display open

I know I'm forgetting something and if I had the cash I would just replace the opti, map, iac, iat, egr, O2 sensors and go from there. I don't have funds to do this right now so hopefully, with help, the issue can be found with minimal R&R.

Thanks so much!

Unplug the egr selenoid from the egr.
Apply vaccum to the egr valve.
Does it hold? does the arm move?
If no - replace the egr valve.
If yes then keep looking for a vaccum leak in the circuit.
I have one near the AIR stuff below the ASR. I'll get around to getting a longer vaccum hose to fix it.

The rest of your issues may be resolved by cleaning and reattaching the grounds.

Yea, do the checks above.
Your symptoms with the SES light are identical to what I had on my 92. Did the checks, replaced the valve, SES light's off.

The H72,74, I've had them on and off for 5 years and just ignore them, it's not worth it to me to dig into them.