Ya might just have the infamous....connector pin/plastic problem. That would be the amp connector that connects to the ref/speed sensor (either side of it!). Bad wiring in between could be, so could the 9pin connector at the firewall at/above the brake booster, could even be bad at DME or associated wiring to, or............ Good luck. Follow Clark's Garage help, and all will eventually come clear. Follow it step by step. Leave NOTHING out. Otherwise, "Who knows"............Just follow the standard diagnostic procedures set forth in the FSM, or the help of
Clark's garage. "its all good!)
5 minute test is GOOD!!........IF.........done correctly!!
Otherwise..........your screwed! Follow the directions to a "T" or........?.
Good luck!