[lincoln_mark_8]

does the car run better at higher rpm or worse. could be a MAF or clogged injectors, or a vacuum leak . if the car runs better at higher rpm then it is prob a vacuum leak and you can test this by spraying carb cleaner around the engine while at a itle and if it idles up higher then your leak is there. If it runs crapier then prob a plugged injector or maybe a faulty fuel pressure reg or pump. highly bad or old gas even. If the gas is considerably old I would drain it and put high octane in it and run it for 15 mins to clear out the old gas