1990 single cam hatch limp mode

[minilurk123]

My car has some weird limp mode thing going on. And in every gear the rpm gets lower that it will do it in. Mostly 4 at 5200 and 5 at around 4000. My speed sensor is bad so would that have an effect? and when it goes into limp mode it has to idle down about 1000 rpms to regain throttle again. Also my car doesnt seem to have any dort of rev limiter in any gear. Also my car smokes white and it smells like gas but spits black liquid out? Head was apparently rebuilt and dont know if the head didnt seat right or if its a fuel problem. Dont see any liquids where they shouldnt be though (water in oil vise versa). -