my 1990 volvo 780 has started to experience a new problem. it takes forever to start and after i get it started it will hardly run. if i take my foot out of the gas it will die and it is running way too rich. yesterday i spent most of the day replacing parts because at first i thought it was from where i changed the mass air flow sensor so i swapped that then i changed the throttle position sensor and neither one of those worked . today i recieved a new jetronic computer for the fuel injection ind it still didn't change anything. Does anyone have any ideas?