HELP

I have an 86 mazda 323 lx 1.6l and i have a problem with it. I washed it about 9 months ago at a gas station using engine degreaser on the engine. ever since then it ran rough. Recently i pulled out my fuel rack and all 4 injectors to find out one isnt spraying. I reversed two injector wires and a different injector stopped and the original one took off. So its a wiring problem. i followed it all the way up to the front drivers side of the hood and the wires go into a metal box thats bolted to the frame. i tested the wire that was bad from there and still no go. I need to find out what this box is and where i can get one. it is a silver box that has 5 wires comeing out into a clip then off to the wirring harness. there is a number on it E5D3 and ND 079960-0282 if anyone has any information on where i can get this or what it is please contact me at chevy__69@hotmail.com there is 2 underscores in my email address. Thanx
Harley