Ive a missan vanette with a ld23 engine. it isn't running right. when stationary and i floor it it belows smoke and sound terrible. when driven it goes flat sounds/feels terrible and forces early gear change untill the revs climb again and gear change is needed again and it belows smoke. ive change the fuel filter and checked the fuel line to the pump and also had the injectors tested and i don't know where to go from here.