In drive, my 01 LX idles around 600 rpm or so but it occasionally drops to around 500. When at 600ish my OBD reader states voltage is around 13.5-13.7, but when it drops to 500-550rpm my voltage will read around 12.5-12.7. Weirdly it will tend to (regardless of AC or not) bump back up to a 600 idle for a minute or two on its own before it drops back to 500ish for a little while and then the process repeats.
I'm not sure if my alternator is dying and so the voltage drop is a result of that, or if my engine is dropping into an idle range that is unintended and so the alternator can't spin fast enough for it. I got the battery load tested to rule that out and it's fine from what I can see. Other threads explain the rpm at idle, but it's unclear to me if 500 is unusually low or just slightly so.
I'm not sure if my alternator is dying and so the voltage drop is a result of that, or if my engine is dropping into an idle range that is unintended and so the alternator can't spin fast enough for it. I got the battery load tested to rule that out and it's fine from what I can see. Other threads explain the rpm at idle, but it's unclear to me if 500 is unusually low or just slightly so.
