2006 grand marquis gs. 35,000 miles. When breaking to slow down at red light car engine revs and surges forward, apply breaks very hard, car still lunging. Put in park and idol goes back
Yesterday, when slowing down and braking to stop, engine revs very fast, surges out of control. Apply brakes and can hardly hold the car back, lunging forward. Put car in park and engine idol goes back to normal. This happened three times in a matter of 1/2 hour.
However, drove car today and it never occurred. What could this be and how can it be fixed. Very apprehensive about driving the car, it could be dangerous. I do have a cruise control also, could this have something to do with it. I was not using it at the time this happened.
You could have a vacuum leak somewhere or the idle air control valve is sticking resulting in the increased engine rpm. The other possibility is someting has gotten inside the throttle body and is preventing the throttle plate from closing fully.