This is either a failed sensor a carboned throttlebody or possibly even leaky injectors. I would check with ford this car may have missed a very important recall. Just call them give them your vin they will run an oasis on it and tell you if it has missed the recall.
Also if you had it on cruise control or even if you did not. They had a recall for cruise runaway this may be the prob
Saturday, February 5th, 2011 AT 1:24 AM