Sorry to take so long to reply - had major computer problems at work.
The car has about 105K miles
H6 .engine
Early in the summer I needed a new alternator (and battery), which worked for about 2 months and then stopped charging. The mech. said it tested good but I made him replace the alternator and it has been charging fine. Then the car started this rough running so the mechanic used his OBD and said 5 of 6 cylinders read bad so he replaced all of them. (I didn't see the codes).
I've had the car about 5 years with no mechanical problems and now engine problems. Have only done regular maintenance.
Does this help at all?
ez30D are very particular about what alternator goes on it. parts stores do not sell anything useful, except useful at giving repeat problems.
subaru dealers want a whole lot for the right mitsubishi USA (new or reman).
this is a new one,...(not a half fixed turd form the parts store). ...I think i would take one from a junk yard if I could see it came out of a EZ30D car, with 3 wires and a mitsubishi USA mark.
$125?, free shipping, and no core charge. (I bought one for my H4 car, ...had it in 2 days, shipped from a warehouse closer then TN)
https://www.dbelectrical.com/products/subaru-outback-3-0l-alternator-01-02-03-04-05.html
other things:
engine grounds.