560sl erratic starting...
 

This car always starts perfectly if the car has just been run (within five to ten minutes after shutting it off... maybe longer).

This car almost always starts just fine if it is perfectly cold... has been sitting a day or two.

The car is very difficult to start (usually but not always) if it has been sitting for about an hour, two hours, etc.

I'd appreciate any directions anyone might suggest for investigation. Thanks so much. PCM

1986 560sl red/black interior

I would look into posts on fuel pressure dropping and/or injector leakdown.

When you say hard to start does it turn? Do you have spark?

Bad start...
 

Had the same problem on my 560 SEL. In mine, it was a leakdown by two (not one) injectors. I replaced them all.

If you have room to climb below the car, you might want to consider replacing the accumulator first - it's not very expensive, and the main duty is to keep the fuel line pressurized while the car is warm but turned off.

For the injector job, search this board - I have given a description on how to do it. You'd want to do all the seals, insulators, etc while you are it - they're cheap too, so no biggie. Your biggest cost will be the injectors. Nice DIY project.