89 560sel running rough..black smoke

[ctc1952]

running rough..black smoke and economy gauge is sometimes in the red at idel. shop in enid,ok says vaccume leak and i got 80% of the hoses on the engine new. it was all the ones they said were leaking. now they say its the fuel dist. but it is new 3 months ago. so all they did was replace what they said was bad charge me 950.00 and set the idel up. but still does the same.. any body got any ideals? chuck