it is, but i have recent experience with something that may be relevant
here and stop you chasing that wild goose.  eld's are solid state, and
the probability of malfunction is ultra small.

my civic, when cold, and coasting down a gentle slope, would speed up
and slow down of its own accord, repeatedly.  all the typical reasons
for this symptom were eliminated.  then i changed the alternators and
for a while the problem went away for a while.  then it started to creep
back, and i suspected the eld, electronic load detector, since this was
clearly something to do with the charging circuit and the alternator had
scratched the itch.  i changed the eld, and zero difference.  everything
else eliminated, but certain of diagnosis, i changed what was otherwise
thought to be a good battery since it was the only other possible link
in that chain - problem completely gone.

conclusion, the eld was detecting current draw outside typical ranges
from an old battery not accepting a charge very well, and the ecu was
causing the electronic idle controls to over-compensate and thus
affecting engine behavior.  in your case, if the ecu is updated to
prevent this potentially dangerous behavior on engine speed, the charge
voltage would be fluctuating considerably instead, and that will show as
light brightness changes.

i therefore suggest that given the age of your vehicle, [you don't state
the mileage], you replace the battery, and consider replacing the
alternator, even if it tests ok.  alternators generally give up the
ghost in the 100-150k range, so you're probably in that zone regardless
of how it tests at the moment.

with respect, that makes no sense.  would you go to a doctor for eczema
and not tell them about also having blood in your urine?  print this
thread if you want to be sure of communicating, but tell him so he can
fix the problem for you!