88 560sl idle and missing and hard starting

[kennedy]

problems started out as hard starting after sitting for an hour, so I changed the fuel accumulator, did not fix
new problem also when hot, put in neutral will some times rev up to 1400
new problem also when hot, going down road, will start missing and clouds of black smoke out exhaust, then will clear and run normal, this first started as a problem after hard starting, high revs and when pulling out of parking lot, no power and lots of back smoke
help
The only other thing I have done to it is cleaned the air slide valve, Is this also called the idle control valve? thanks