I have a 1986 Rx-7. I purchased an auto meter tach that was used on an Rx-7 but have no idea which wires go where... I have searched autometers website and cannot find any information on the wiring for this. Can anybody tell me which wire goes where. I have a red, green, black, and white wire.

Also I have switched from s4 to s5 intake,installed kill switch, removed all emissions stuff, added header and true dual exhaust all the way back, and removed cold start stuff from throttle body. The car ran fine until I pulled the gauge cluster and added my own gauges(water temp, oil temp, and pressure. Now the car has a really bad lope to it and just pops and backfires out the exhaust when I press the gas pedal. Seems like primary injectors are not coming on or something. I have had this problem intermitently before I did any work to the motor any suggestions? I have checked the obvious vaccuum leaks, compression, coils shoot spark, and looked around for loose wires.
Thank you