Possibly a failed battery, go get it checked out first. and Check all your ground connections to the battery and to the motor. go from there....
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)