My Renault Espace is sick!

:cry: I have a renault espace. Rn.2l. L plate year 1994-1993. And it has done 117 on the clock.
The problem I am having is the acceleration isant keeping up with the foot and it gluggs, black smoke rumbles from the exhaust, it either stalls or struggles to maintain the rpm. We filled up with more fuel and she was fine till we tried her the next day and we have it all over again. I know its not out of fuel and it states that it isant(not that that is always true the fuel bobbing thing could lie). Once the black smoke has blown through its okay for a while. Thats the first question. Next my battery is draining on a nightly basis, we charge it up for 1/2 hour and its fine. Could this be the immobiliser, we had the battery checked and it is charging. Please help we have spent so much time and money doing this up I just cant b with out this family wagon.