Foxbody Surging Idle When Warm: It’s Fixed (Update - It’s back)

9 months after this issue first started, I’ve found the cause.
A lot of time, frustration and money are gone but I’ve finally got a reliable running car again.
Ultimately, it was the computer but not the capacitors. It has a bad ROM chip that can’t be replaced. A different computer fixed the issue.
What did I test or replace that didn’t fix it?:
Base Idle Reset
Pull engine codes
IAC
TFI
Grounds
Distributor
Fuel pump
Fuel pressure regulator
Throttle body
Coil
Fuel injectors
EEC relay
Fuel relay
Fuel injector harness
Mass Air Meter
Spark Plugs
Salt n Pepper Shakers
I’m sure I’m forgetting a few things #foxbody #foxbodymustang #mustang