Garry wade

My 2016 2.7 petrol HiAce van has flat spot on accelation first thing when cold. Have changed spark plugs so far.

Hello , l have a 2016 HiAce 2,7 petrol Auto . The problem l have is l have flat spot on acceleration from idle but it doesn't do it all the time. The Toyota dealer wants to change different parts to find the problem. Would like to hear if any one else has had this problem. Before l spent Too much money . Thankyou