Unexpected Surprise (voltage regulator)

[TheSubaruLegacy]

I just replaced my Coolant Temp Sensor. (Tip from Josh). No doubt a good investment. (Engine was sputtering before and after shifting). Problem still existed; until I swapped the ALTERNATOR. Turns out a "spike" in the voltage regulator was the culprit. So far so good.
This Legacy was the best investment ever. ($300.00) all I did was replace some bolts on the exhaust (.60 cents ), 2 rear struts,
($250.00, local garage of course my friends), and a used alternator ($30.00). Now I have a near mint Legacy (with no directionals) for $580.00. Oh yeah, 66,000 miles. (That's like my fathers' Nissan with 1,000 miles).

[professor]

yeah I think a lot of folks have regulator problems when they get multiple code and CEL, and hesitation.

My car ran much smoother after I replaced mine.