Please HELP!!

Ok I recently bought a 96 talon esi, not running, only to find out that the dude that owned it last blew a piston and scared the block so I bought a new core motor and dropped her in. went through some of this and that till finally it turned over. but now it wont stay running unless I unhook the device hooked to the egr valve, does anyone know what this is and why it would affect my car like this...please help, Ive come so far!!! once again its the plastic like device that has a chrystler symbol on and is hooked to the egr valve and vac.



Thanks,
talon96

Its an egr seloniod/idle control valve, if anyone wants to know...