Well, I got 5 years and 1 month out of the original factory battery. From comments I have seen here, that's pretty good.

After sitting for about a week, the battery is stone dead.

My question is: After I install the replacement, do I need to reinstall my custom tune from Alternative Auto? Will the computer reboot back to factory specs despite the factory tune being "saved" in the Xcalibrator?

 

everything should be ok just change the battery.

 

The adaptive learning in memory will have been lost , so it'll take a little while for the computer to relearn it. Another thing is if you have a senor starting to go bad and the computer was using the adaptive memory data to compensate for it you might notice it running differently now ...

 

Thanks.

The strange thing for me today is that my on-line shopping proved that my local Ford dealer has the best price on a replacement battery. Oh, and that the Sears website says they don't have ANY batteries for ANY 2006 Mustang.

 

That's strange about Sears , I always replace the OEM one when it craps out with a Sears battery since they have a great warranty. I have one now in my 05 and I would think it would be the same one as in your 06 ...

 

5 years and 5 months on mine now; i am always caareful to be sure the radio is off before shutting it off; i have had 3 drains in the past couple of years tho.