Have Toyota Questions? Ask a Mechanic for Answers ASAP
OK for the alarm issue, if its a factory alarm, exit the vehicle and place key in the drivers door, turn it to the lock position and then to the unlock position, enter car and try to start.
For the idle condition, I would recommend first cleaning the throttle body, and throttle plates, they most likely have carbon build up on them, by replacing the battery the throttle body loses its position memory.
Thank you for using Just Answer.Please press finish and rate to rate the service provided.