Hi, I have a 93 Mercury Tracer, Mileage 110,000 automatic transmission. It run fine but when engine is idle and gear is in park position. RPM nedle would keep moving up and down between 1000 and 2000 RPM. Engine would sound like someone is pushing gas paddle down and release, down and release for few times. Then engine would stop, engine/battery check lights would turn on but when I turn ignition key, engine would start immediately. If I leave it in Park gear, same cycle would repeat. I have to immediately change the gear and move the car to prevent engine stopping.
I have noted that engine doesn't stop if I put my foot down on gas paddle little bit. Problem happens only when gear is in Park positon.
Second problem is sometimes engine would not start unless I change gear to nuteral position.
Your help would be highly appreciated.
I JUST ASK MY BOYFRIEND AND HE SAID TO CLEAN THE BUTTERFLY VALVE THE ONE THAT SUCKS IN AIR AND CLEAN IT AND ALSO THE INJECTORS THAT WOULD DO THE JOB JUST GRAB SOME CARB CLEANER AND START CLEANING IT SHOULD HELP ITS SOUND LIKE MY PROBLEM EXACTLY MY CAR IDLES WHEN ITS IN PARK WHEN I HAVE MY FOOT ON THE BRAKE IT DOES IT SPONTANEOUSLY IT DOESN'T DO IT WHEN MY FOOT IS ON THE GAS AT ALL. MY BOYFRIEND CLEANED MINE ABOUT THREE MONTHS AGO AND ITS BEEN FINE UNTILL KNOW ITS ACTING UP BUT AS SOON AS HE CLEANS IT OUT AGAIN IT SHOULD BE FINE FOR A COUPLE MONTHS. I REPLACED SO MANY PARTS AND I SCHOULD OF JUST SPENT $5 ON SOME CARB CLEANER IT WORKS AND EVEN IF ITS NOT YOUR PROBLEM ITS BETTER THAN SPENDING HUNDREDS OF DOLLARS ON NEW PARTS.
December, 21, 2007 AT 10:46 PM
[/quote: d9bdbaf2fd] I HAD THE SAME THING HAPPEN. IT TURNED OUT TO BE THE AIR IDLE MIXTURE VALVE HOPE THAT HELPS