I recently delved into my Delorean because it has never seemed to idle correctly when cold. I've had it looked at by various mechanics, and had checked out numerous other possibilities like micro-switch, idle motor, etc. etc. but nobody ever came up with the answer.
I pulled the diode up that leaves the idle conrol ECU, It sits just under the box in the wiring. Strangely enough, the Diode appeared to be pointing backwards.
I didn't have confidence in my diagnosis, but have several Deloreans so I pulled the Diode on one of the others.
Both Diodes had the same model and number on them and appeared the same but the male and female ends were on opposite sides.
This was a factory install. The connectors were the same on both cars with the wiring male connector on the side nearest ground, and the wiring female side on the wiring nearest the ECU. Even though you could see the diode picture that it was directed backwards, I checked continuity, and open circuit, and sure enough, it was backwards. Whoever installed them, placed them in the connectors the way they fit, but, since the diodes had male and female on opposite ends, one was backwards and not providing a ground. This is a consideration worth noting in cars with long term unresolvable cold idle problems.