i have a 95 neon sohc. i bought an air/fuel ratio guage. to hook it up i need to splice it to the o2 sensor on the exhaust manifold. there are four wires..two white a grey and a black...i called the dealership and they have no idea where im suppose to hook it up...the directions said the signal sender wire, but which one is that?

 

On my 97 it's the black wire with a dark green tracer.