1987 190e, 2.3
 

I just bought the Mercedes and it idles sometimes a little rough and a few days ago it stalled and wouldn't start again. The next day it started first a little rough and after a few more tries it ran smoother. It almost seems it is not getting fuel. It always seems to try to start.
Does anyone know what that could be?

Also I wanted to check the spark plugs but the wires are so tight I am afraid to rip the wires. Is there a special tool to pull them?

Yes, there is a special tool to pull the plug wires. It's not expensive, but you need one.

see 103-0037

http://www.peachparts.com/diy/mb_tools/mb_tools.php?page=22

As far as starting problems, the OVP, OverVoltage Protection relay, A silver can with a red top and a fuse or two, needs to be checked. Vibration causes the solder joints to break and there could be a bad fuse. Open the can and resolder the connections.

The large solder joints in the fuel pump relay can also crack and open. Resolder them.

Perform searches on OVP and fuel pump relay and you'll see lots of entries. Cracked solder joints in European cars are almost a given.

You'll need to check the 'duty cycle', so do a search on that too.

Also, check the DIY section:

http://www.peachparts.com/shopforum/diy-links-parts-category/

etc