your metro comes in calif. and fed 48 flavors.
here is fed page 1 and 2
its a shame , my car has external Ignitor, yours is inside ecu , and the spark is monitored internal to the ecu on you year, bah.
so cut the ppl wire( purple) to ecu pin9 CMP input. aka ,
see page 2 , this power feed top right corner is yoiur Ignition switch KEY ON , input.
this is from pub. lib. any gay/gal has this access, btw.
this example will die in 12hr, so DL it.
zip file.
cutting the pin nine ppl wire, will in fact set dtc code 42 , but will clear itself.
this kills spark and fuel both , one wire and will not blow anything up or hurt the ecu.
tell me how it works.
cheers
schematics for your car XFi metro
http://kick-fix.com/look/metro/