the battery on my 06 gt goes dead after car sits for a few days. I have replaced the battery and had alternator checked and its
okay. The battery charges right up after being jumped and the car then starts with no problem. Problem occurs when car is not
driver for a day or two. Been told it may be the Master Power Relay but I am unable to locate it. Any ideas?

 

if you have the stock radio, it could be draining the battery. fuse 56 in the engine bay is for the radio. my 06 was doing what you describe, i just pull the fuse now if i am not going to drive it the next day.

 

Same exact thing happened to me in my 1999 GT. I thought it was the battery and alternator, replaced both and within a couple months it was back to dead battery after sitting just a couple days.

The problem was the starter drawing too many amps on COLD STARTS. Normally a starter draws about 180 amps on cold starts, mine was drawing near 400 amps. After so many cold starts it was slowly killing the battery to the point of lack of amps. Remember it's amperage that starts your car, not volts. Have your starter checked to see how many amps it's drawing on cold start ups.

That fixed the problem with me. Good luck!!

 

You have a "parasitic drain". Google that and you'll find step by step instructions on how to track down the culprit. You'll need a decent multimeter. It's also fairly easy to do. Good luck