Update: Last night my coolant gauge was acting weird. I'm guessing that could have to do with the SIG-RTN wire as well. It was going all the way up and it never does since i put in my new radiator. I dont know what to do lately, i can drive the car no problem, it just these weird things im having problems with. The idle was fine last night. jritcher, could the problem in the wiring harness only be the SIG-RTN wire right. not the black/white the gray/red wire? The gray/red wire is the one that is in the middle of the engine harness.