Tried to do this one without asking but........
Did all the 'noobe' searching that I could on the problem I am having (rough start up idle) and have narrowed it down to a possible faulty OVP. In my searches I found where the location of it is, but am uncertain which one it is. I took a picture and I assume it is either the chrome one, green one or white one. (1990 500SL)
Thanks for the help on this one.