i have an 03 mach 1 and i just took mine up to ford today to get mine checked out, it makes a ticking sound from the engine mostly on the the driver side, and they returned it to me saying that this is typical among the 32 valve engines(cobra and mach1), so all they did was torque some screws and gave it back to me, and said that this is and has been under investigation, also they said this does not effect the performance in any way