Battery/alernator??

[Cougar_Marauder]

So i live in wisconsin and have been gone for a few weeks. The weather has been nice and cold. The other day I went to start my MM and the battery was dead. I think it is the original battery so I thought it was just its time. I jumped the battery and drove the car for about an hour. I noticed my voltmeter was running low at about 13.8, i thought because the battery was not at full charge..? but even after an hour it was still low. I bought a new battery(did not put it in yet), but now 3 days later the old battery seems ok, no troble starting and now the voltmeter is running normal (a little high even at 14.4 this morning). Is it just the 5 year old battery mixed with the cold weather?

Also after I jumped the battery it seemed like the tune i put on was back to stock. That doesn't seem right to me. The shifts seemed soft and sluggish. I haven't had time to plug my tuner into it to see what it says yet.

[GreekGod]

... Is it just the 5 year old battery mixed with the cold weather?...

A good battery with a low charge will not work well when trying to start a car with temps below 20 degrees F. Same for a dying or marginal battery. Warmer weather, and they usually work well.

5 years is probably nearing the end of it's life. My '03 MM's battery just died this winter. and it is probably the original (6 years old).

I have an ancient (over 10 years old!) Sears/Die Hard Gold in my truck that still holds a charge, so I am going to try a # "65" in the MM.