Notnormal

I have a 97 Lexus es300 and the auto shop told me the computer is bad because all my lights will come on and it will have a miss fire on the same cylinder. All new parts thrown at it and that's the only thing that hasn't been replaced. Does this year computer have to be flashed? My friend has the same year car and same tranny. He just got rear ended. Will it working just swapping it out. Please help asap. Thanks