1992 Chev Cavalier Z24. runs rough at idle and sometimes stalls. Black exaust exits tailpipe and gas mileage is terrible. Mechanic told me it was a melted vacuum hose coming from MAP sensor under plenum but could not find the culprit...suspecting MAP sensor based on internet research but not sure. higher RPM's prevent stalling at low speeds...so we drive two-footed (one on gas and the other on brake). I'm no expert and really don't know where to go from here without spending another $500 to have the mechanic fix the darn thing.
Please help me....16 yr old daughter drives the car and don't need her to have problems and potential dangerous situations.

 

IAC may need to be cleaned IAC= Idle Air Control should be located on or very near the throttle body.
The throttle body and plate could also be dirty(carbon build up) causing rough idle stalling.

the EGR stuck open could also cause poor idle but it sounds like its could be running too rich....

 

you should get a service engine soon (SES) light. you can get the code by putting a jumper between the A and B terminals in the connector under the dash and count the blinks of the SES light. - I see In2pro recommends IAC as I was typing this - I agree. also clean the EGR. check the air filter - I helped a Dad/Daughter at Autozone last night with a similar problem - with the air filter removed, it ran fine. they ahd a MAF code MAF sort of replaced MAP in the mid 90's or as we went from OBD1 to OBDII

 

Welcome to the forum ShadeTreeJack

 

intermitent SES light

 

It would defiantly be a good idea as ShadeTreeJack suggested to have the codes read, write them down and then cleared.
before jumping on them wait and see which ones come back and go from there as the light going off and on can mean the issue clears up and is no longer flagging.