Why would a 2001 ford focus run fine on the highway then you pull in your driveway put in park it idles rough then stalls.It will start up but stalls out right away stays runnin if you keep givin gas?
This just started happening to my 2000 Ford Focus SE. I am investigating the Mass Airflow Sensor, which affects idle as well as the ECM (engine control module) which apparentl…y affects idle, too. I suggest starting there. I had the same problem. There is a vacuum line that goes from the PCV valve to another port behind the engine - mine had a crack right at the elbow. Listen for a hiss or spray carb cleaner around it and look for the engine to rev up. The new vacuum line is covered in a foil, probably to prevent the engine heat from degrading it. (MORE)