Does sound like the battery has a dead cell. All batteries have a sticker on them showing the date of manufacture. Any reputable store can use that for warranty purposes.
Also, when testing charging voltage, go to a lower scale with one place after the decimal point for more accuracy. 13.75 to 14.75 volts is acceptable. 13.6 is low but would be rounded off to 14 volts.
You can also put a charger on the battery on the lowest setting for an hour, then see how long it holds up. If there's no change, suspect the battery.
The alternator should also be load tested with a tester than displays "ripple". Most Nippendenso alternators are rated at 90 amps. If you can only get one third of that and the ripple is high, suspect a defective diode. 30 amps is barely enough to run the fuel pump and computers with little left over to recharge the battery even though the charging voltage might appear to be okay.
Wednesday, January 4th, 2012 AT 11:06 PM