Misfire developed while parked for a few days

[69GT]

Have an 03 5-Speed Mach with a misfire. I parked it last weekend running fine. fired it up today and there it is. Causing slightly rough idle (Shaker helped me see that ) and slight stumble at throttle tip in and of course rougher acceleration. It's not showing any codes. Car only has about 42,000 miles on it.

Only Mods to car are:
SCT with BAMA tune.
JLT CAI
ported exhaust manifolds and BBK full exhaust.

This is my first 4V OHC engine. The most advanced thing I had before it was an 86 2.3 turbo 86 SVO.

What usually causes this? I am guessing a coil? What would you do?

Thanks!

[69GT]

Fixed problem. It was a coil. Connector on coil side was damaged and repaired badly. Guy who had it before me must have been trying to save a buck. Bought a new coil and 15 minutes late Mach 1 no longer has a cough.

In addition to a cold air intake. I am declaring the shaker hood a misfire warning indicator.