I got so fed up with my car problem I called out the AA yesterday. The first thing they did was to make a short phone call and got my 5 digit code simply from my registration number.They then started the car using the emergency start procedure. They said either the chip in the key is faulty or the transponder in the car is faulty.The problem did not end there however as I now have an even worse problem the engine runs terribly now miss firing, backfiring and stalling. They then did a very detailed examination of all the electrics, ignition system,wiring and fuses etc found nothing wrong. All these problems have occurred since I replaced a faulty coil pack! Can anybody help as I haven't a clue what is going on.