Timimg decreases when idling at stop

[GeoRandy]

I have my timing set at 8* and my car runs great.
I have a Scangauge and it keeps me well informed.
My trouble is that when I am driving and stop at a stoplight,
sometimes my timing drops down to 3* instead of returning to 8*
Sometimes is goes back to 8*, but when the radiator fan comes on and I add other electrical drain like the heater fan, wipers, etc
that is when the timing drops down to 3*
What could be the problem?
Thanks in advance. No pun intended.
Randy

[MikeCStig]

It sounds like your engine computer just doing its job. You can advance the timing manually, but ignition timing is one of those things the the ecu adjusts slightly at various times to keep your engine running optimally.

[GeoRandy]

Yes, but it never dropped to 3 or 2.5 before when the radiator fan came on or I turned on the cabin fan. Now it does. I put a new alternator on but that didn't fix it.