Ok so I found that on 88-91 there is a black/orange ignition ground and a black case ground. Then on 91-93 there is a black, black/white and an orange ground. Doesn’t say if it’s a case ground or not but maybe the brown is actually orange?
Well just an update, I figured out what was going on with the stang. My heads with the new ford racing valve covers were too high so when I put my upper intake on, it was hitting and left a gap between upper and lower manifolds. Thanks to general kartheif for telling me to track my grounds. Anywho, fixed that and she is running great, so far. I only ran her for 10 minutes but could do so with the maf sensor plugged in and everything sounded right.
So, with that done I figured I would tackle the front suspension, brakes and steering. Got new calipers and waiting on the rack tomorrow. Cleaned up a mess from the rack leaking and collecting dirt, new ball joints, sway bar, bushings, tie rods, and need to find someone to weld a steering knuckle to replace the rag joint. Should be ready to drive this weekend hope we have a nice couple of days.