87 Cherokee 2.5ltr constant stalling

I'm having issues with my old 310k Cherokee. constantly stalls at low rpm's (feels like it " catches up " when gas applied).Had tune up and oxy sensor replaced. Seems like its getting too much gas?? . Car smells almost burnt after medium trips??. Ps heater motor blows cold air only (probably unrelated). any thoughts on where to start looking for solutions..

Thanks in advance.