2005 Mustang With Extra Unidentified Key Fob; No Crank No Start, Sometimes


New Member
Jan 8, 2017
Hello all!
I am the proud new owner of a 2005 GT vert I purchased used from a dealer. This will be my 2nd mustang. However when I purchased the car it came with an extra key fob. The fob is on both key sets. And I presume it's an aftermarket security system. There's a button on the center of it, when I push it the key lights up, however, nothing happens.
Now for the weird part... sometimes, not all the time, when I turn the key over the car has no crank no start. After 30-40 seconds after turning the key to prime it, it will turn over and run perfect. I assume it's the security anti-theft system and the key fob is to blame. However, the 2005 mustangs are new to me and any advice would be appreciated.
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