I have a 2007 ford ranger. It sometimes wont start and the auto theft light flashes fast......then a while later it will start with no problems. We have taken it to a dealer twice the first time they said it was the computer and changed it....it still happened after that, we took it back to the dealer and they said there is nothing wrong with it. Sometimes when driving the speedometer goes to zero and also the tac and the engine light cones on but then goes off and the speedometer and tac start working. It happens periodically. What could be the problem? Anyone have this problem?