I´ve been having rough idle problems for a while. Today I adjusted the valve timing with the offset woodruf keys (i changed the chain tensioner and the chain wear pads and the chain a while back).
Before changing the woodruf keys on the cam shaft the timing on the passenger side cam was about 13 degrees ATDC and the driver side cam was about 18 degrees off.
To make a long story short - my idle was quite rough before, now it is rock steady and the power and driveability is significantly improved.
This is a cheap fix and it relly helped me. Takes about 3 hours if You got the parts.
1984 500 SEL