Did you get the timing reset ok? Is the idle too fast or too slow? If all you did was to turn the distributor to retard the timing, I don't know how that would change the idle speed unless you adjusted the speed after changing the timing. As I recall from the dim dark past, retarding the timing used to make my engines idle more slowly. You might try looking in the 700/900 FAQ's. These cars use the same engine and there is are ideas for working on engine idle problems. You'd want to study engines of a similar age to yours because the computers do change. There is also a procedure in the Bentley manual for setting the base idle and CO adjustment on the Air Mass Meter. If you don't have this manual, you should get one (try Ebay or IPD). I have saved the cost many times over. Give us a little more specifics on your problem, maybe we can give better help.