idle's from 1000 down to 400 repeatably and dies

[Hell_raiser]

i think i may half to pick up a hole new engine wiring harness is this possible its for a 3.1 mpfi it has random wire connected rite to the battery . i need 2 know if i can get one used and how much its gong to run me. wont Corsica 3.1 harness work 2. the harness needs 2 have all the wiring for sensors and stuff let me know if u can buy these and price in cad plz thanks !