Purchased 2004 cadillac and while driving looses acceleration, no warning if I stop and shut off car and restart problem goes away. Intermittent pro blem. Problem will pop up again without warning. Car dealership cannot fix the problem, car has been into dealership several times. Can anyone help to troubleshoot this problem? I did bring car in when problem was happening they retrieved the code but it did not indicate the error. Now the car needs a #3 ignition coil and I am trying to find out instructions for replacing this part. Car is sitting in my driveway inoperable.. If anyone has any information would greatly appreciate the help.