I looked at the schematic at the ignition module and the pile of stuff hung off it. UGH For instance what is 4/45 "Variable intake manifold solenoid"
It looks like some choke control. UGH again

Here's my hunch, yank the ignition module. Clean the gold edge contacts with
a clean red mechanics rag soaked with 90% or higher proof isopropyl alcohol,
then apply a thin coat of dielectric silicone and re insert.
Corrosion on module connectors might upset the works.

See what happens, shouldn't take much time to see if that kills the OBD code.

Bill