All,
I purchased a 2007 GT a while back and am wondering if there is a way without a tuner to tell if the previous owner installed a custom tune and left it in? The reason I ask is I get a knocking noise almost like cam phasers when on 87 octane. When I go to 93, the noise seems to go away. Thanks as always for the help

 

What mods did it have when you bought it? I guess you tell if it came with mods that would require a tune.

 

Thanks for the reply. It didn't have any mods when I got it. Does not seem that the car has a tune by the way it performs but it is odd that the octane will affect the knock.

 

There is really no way to tell, but I doubt it. Ford Diagnostic Tool, will say how many times the computer has been reset, but if you store your car, or have replaced the battery, these will also show up on IDS as resets. I use to work at ford.

 

no way that i know of, to tell if it has a custom tune. but the fact that it does not ping with higher octane points to a custom tune. use 93 until you get a hand held tuner and are able to upload a different octane tune.

 

I don't know if the newer tuners do this but I have an Xcal 2 that the display went out twice, I had to have it repaired by SCT both times and the second time around the stock tune was lost. When I connected it to the car after the second repair, it detected that the current tune wasn't the stock tune and it wouldn't let me upload any tunes because it wasn't returned to stock.