Protege5 w/ a misfire code I can't figure out
 

We have a 2002 Mazda Protege 5 we bout a few months ago.

It ran great until two days ago when the check engine light stared flashing. We stopped driving it and put a computer on it. The code came up misfire cylinder 1. We have swapped the coil, plugs and wires. It runs fine in first but as soon as it switches to second it misfires.

The only code we get is the misfire in cylinder 1.

Any suggestions?