Thanks, Alain for your response and I will check the things listed. I recently had a timing chain, rails... as a precaution. The plugs were changed, but I suppose I should check them anyway. Rotor and cap look perfect. I bought new ones when I bought the car (assuming they needed replacing) but didn't even install them. I will try to find the test for the Idle Control Unit and Idle Air valve but I am all tied up for the next 2 weeks so I don't think I will be able to get to it. For now, I will hold off on just replacing the fuel pump relay until I know it's bad. I saw the CD had a test for the relay but it seems that the relay has to be installed and then I don't know how to get the leads from the meter in there.
Thanks again and I will return as shortly as possible. Didn't want to leave without responding to your post. I have to do some Biz travel on and off for the next few months. I would rather just work on the Benz!

Steve
'85 500SL (Euro)