My 1996 sd was having random starting issues and coud not figure it out also it was running very rough sometimes. Found out that when the back door was open it would start fine. I narrowed it down to the door jam switch and found that in order to start and run well i had to take off the switch and ground the wire right to the frame with the screw. I have to make sure it stays connected well and the problem goes away. Then also sometimes it still wont start and I have found that I also sometimes have to get out and turn my key in the drivers side lock back and forth, then get back in and it starts. (security malfunction?) I am lost and dont have any more ideas and this is way to strange for me to figure out. Any help would be great.
Thanks