If you have another vehicle I believe they loan tools at autozone. So you could rent a scan tool and verify that way. Bring the scanner home and swap the coil to another cylinder and check if it follows. Just a suggestion to try to save you some dinero$.
2004 GT current mods : CAI, BBK Short throw shifter TB and UDPs, SCT x3/SF3 with BAMA Perfomance tunes Roush body kit, roush side skirt exhaust and paint.